161657728 has 32 divisors (see below), whose sum is σ = 322677000. Its totient is φ = 80672256.

The previous prime is 161657701. The next prime is 161657753. The reversal of 161657728 is 827756161.

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×161657728² = 52266442044243968, which contains 22 as substring.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 93738 + ... + 95446.

Almost surely, 2^161657728 is an apocalyptic number.

It is an amenable number.

161657728 is a deficient number, since it is larger than the sum of its proper divisors (161019272).

161657728 is an equidigital number, since it uses as much as digits as its factorization.

161657728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2462 (or 2450 counting only the distinct ones).

The product of its digits is 141120, while the sum is 43.

The square root of 161657728 is about 12714.4692378408. The cubic root of 161657728 is about 544.7519877073.

The spelling of 161657728 in words is "one hundred sixty-one million, six hundred fifty-seven thousand, seven hundred twenty-eight".