165253921 has 24 divisors (see below), whose sum is σ = 196335360. Its totient is φ = 138664512.

The previous prime is 165253909. The next prime is 165253931. The reversal of 165253921 is 129352561.

It is not a de Polignac number, because 165253921 - 2⁷ = 165253793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165253931) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 691320 + ... + 691558.

It is an arithmetic number, because the mean of its divisors is an integer number (8180640).

Almost surely, 2^165253921 is an apocalyptic number.

It is an amenable number.

165253921 is a deficient number, since it is larger than the sum of its proper divisors (31081439).

165253921 is a wasteful number, since it uses less digits than its factorization.

165253921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493 (or 486 counting only the distinct ones).

The product of its digits is 16200, while the sum is 34.

The square root of 165253921 is about 12855.1126405022. The cubic root of 165253921 is about 548.7618661029.

The spelling of 165253921 in words is "one hundred sixty-five million, two hundred fifty-three thousand, nine hundred twenty-one".