161555688 has 128 divisors (see below), whose sum is σ = 521856000. Its totient is φ = 45351360.

The previous prime is 161555659. The next prime is 161555699. The reversal of 161555688 is 886555161.

161555688 is a `hidden beast` number, since 1 + 6 + 15 + 556 + 88 = 666.

It is a super-2 number, since 2×161555688² = 52200480650306688, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 88303 + ... + 90113.

It is an arithmetic number, because the mean of its divisors is an integer number (4077000).

Almost surely, 2^161555688 is an apocalyptic number.

161555688 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161555688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (260928000).

161555688 is an abundant number, since it is smaller than the sum of its proper divisors (360300312).

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

161555688 is a wasteful number, since it uses less digits than its factorization.

161555688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1892 (or 1882 counting only the distinct ones).

The product of its digits is 288000, while the sum is 45.

The square root of 161555688 is about 12710.4558533516. The cubic root of 161555688 is about 544.6373459201.

The spelling of 161555688 in words is "one hundred sixty-one million, five hundred fifty-five thousand, six hundred eighty-eight".