161856604 has 72 divisors (see below), whose sum is σ = 358174320. Its totient is φ = 63431424.

The previous prime is 161856599. The next prime is 161856631. The reversal of 161856604 is 406658161.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 353944 + ... + 354400.

Almost surely, 2^161856604 is an apocalyptic number.

161856604 is a gapful number since it is divisible by the number (14) 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 161856604, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (179087160).

161856604 is an abundant number, since it is smaller than the sum of its proper divisors (196317716).

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

161856604 is a wasteful number, since it uses less digits than its factorization.

161856604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 627 (or 618 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 37.

The square root of 161856604 is about 12722.2876873619. The cubic root of 161856604 is about 544.9752860325.

The spelling of 161856604 in words is "one hundred sixty-one million, eight hundred fifty-six thousand, six hundred four".