165229821 has 16 divisors (see below), whose sum is σ = 245273920. Its totient is φ = 109933200.

The previous prime is 165229789. The next prime is 165229837. The reversal of 165229821 is 128922561.

It is not a de Polignac number, because 165229821 - 2⁵ = 165229789 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165229891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8271 + ... + 19971.

It is an arithmetic number, because the mean of its divisors is an integer number (15329620).

Almost surely, 2^165229821 is an apocalyptic number.

It is an amenable number.

165229821 is a deficient number, since it is larger than the sum of its proper divisors (80044099).

165229821 is a wasteful number, since it uses less digits than its factorization.

165229821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12233 (or 12227 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 165229821 is about 12854.1752360857. The cubic root of 165229821 is about 548.7351883619.

The spelling of 165229821 in words is "one hundred sixty-five million, two hundred twenty-nine thousand, eight hundred twenty-one".