161635256520 has 64 divisors (see below), whose sum is σ = 488607387840. Its totient is φ = 42773702400.

The previous prime is 161635256501. The next prime is 161635256533. The reversal of 161635256520 is 25652536161.

It is a super-2 number, since 2×161635256520² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5125351 + ... + 5156790.

It is an arithmetic number, because the mean of its divisors is an integer number (7634490435).

Almost surely, 2^161635256520 is an apocalyptic number.

161635256520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161635256520 is an abundant number, since it is smaller than the sum of its proper divisors (326972131320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161635256520 is a wasteful number, since it uses less digits than its factorization.

161635256520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10282286 (or 10282282 counting only the distinct ones).

The product of its (nonzero) digits is 324000, while the sum is 42.

It can be divided in two parts, 161635 and 256520, that added together give a triangular number (418155 = T₉₁₄).

The spelling of 161635256520 in words is "one hundred sixty-one billion, six hundred thirty-five million, two hundred fifty-six thousand, five hundred twenty".