161665872 has 40 divisors (see below), whose sum is σ = 421553376. Its totient is φ = 53383296.

The previous prime is 161665843. The next prime is 161665897. The reversal of 161665872 is 278566161.

It is a super-2 number, since 2×161665872² = 52271708339040768, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10603 + ... + 20874.

Almost surely, 2^161665872 is an apocalyptic number.

161665872 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

161665872 is an abundant number, since it is smaller than the sum of its proper divisors (259887504).

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

161665872 is a wasteful number, since it uses less digits than its factorization.

161665872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31595 (or 31589 counting only the distinct ones).

The product of its digits is 120960, while the sum is 42.

The square root of 161665872 is about 12714.7894988474. The cubic root of 161665872 is about 544.7611354000.

The spelling of 161665872 in words is "one hundred sixty-one million, six hundred sixty-five thousand, eight hundred seventy-two".