1381161600

Appears in sequences

• Numbers k such that gcd(sigma(k),k) = k/5.at n=34A067237
• Numbers k for which sigma(k)/k - 4/5 is an integer.at n=8A218427
• Refactorable numbers (A033950) that are simultaneously arithmetic (A003601) and harmonic (A001599).at n=8A331666
• Harmonic numbers m with a record number k of distinct prime numbers p_i (i = 1..k) that do not divide m such that m*p_1, m*p_1*p_2, ... , m*p_1*...*p_k are all harmonic numbers.at n=6A335370
• Harmonic numbers with a record number of harmonic numbers that can be generated from them using an iterative process of multiplying by primes (see Comments).at n=11A335371