165991728 has 40 divisors (see below), whose sum is σ = 490071808. Its totient is φ = 47426112.

The previous prime is 165991717. The next prime is 165991741. The reversal of 165991728 is 827199561.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 246676 + ... + 247347.

Almost surely, 2^165991728 is an apocalyptic number.

It is an amenable number.

165991728 is an abundant number, since it is smaller than the sum of its proper divisors (324080080).

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

165991728 is a wasteful number, since it uses less digits than its factorization.

165991728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494041 (or 494035 counting only the distinct ones).

The product of its digits is 272160, while the sum is 48.

The square root of 165991728 is about 12883.7777068684. Note that the first 4 decimals coincide. The cubic root of 165991728 is about 549.5773369839.

The spelling of 165991728 in words is "one hundred sixty-five million, nine hundred ninety-one thousand, seven hundred twenty-eight".