DescriptionThis paper derives new structural constraints on hypothetical odd perfect numbers using congruence-based exponent restrictions and cyclotomic reductions. By analyzing both Touchard branches under the classical Eulerian form, we show that primes congruent to 1 modulo 3 necessarily force the appearance of primes congruent to 1 modulo 5. The results are unconditional, non-computational, and integrate naturally with factor-chain and abundancy arguments, significantly narrowing admissible configurations. AbstractWe study structural consequences of the classical Eulerian form of odd perfect numbers under the dichotomy induced by Touchard’s congruence conditions. Focusing first on the branch where 3 does not divide the number, we establish a rigid restriction on the exponents of prime divisors congruent to 1 modulo 3. We show that the minimal admissible exponent choice forces the appearance of prime divisors congruent to 1 modulo 5 via a cyclotomic reduction. This phenomenon propagates through both Touchard branches, yielding a unified structural consequence applicable to all hypothetical odd perfect numbers. While this does not resolve the existence question, it provides a non-computational framework that significantly narrows admissible configurations and integrates naturally with factor-chain and abundancy arguments. Note on Scope and Interpretation Note.The unified extension across both Touchard branches stated in earlier drafts relied on an auxiliary claim concerning the prime divisors of σ(3^{2β}). Subsequent examination shows that this claim does not hold in full generality. Accordingly, the present version of this work should be read as establishing a fully rigorous and unconditional structural constraint in the Touchard branch where 3 does not divide the number. The discussion of the complementary branch 3 | N is included as a conditional extension and as an open direction for future research, rather than as a proved theorem. The main result and its cyclotomic forcing mechanism remain valid and independent of this extension. Keywordsodd perfect number, Euler form, divisor sum, cyclotomic polynomial, Zsigmondy theorem, abundancy index