165721244 has 24 divisors (see below), whose sum is σ = 313589808. Its totient is φ = 76176000.

The previous prime is 165721229. The next prime is 165721267. The reversal of 165721244 is 442127561.

It is a self number, because there is not a number n which added to its sum of digits gives 165721244.

It is a congruent number.

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, 6704 + ... + 19400.

It is an arithmetic number, because the mean of its divisors is an integer number (13066242).

Almost surely, 2^165721244 is an apocalyptic number.

It is an amenable number.

165721244 is a deficient number, since it is larger than the sum of its proper divisors (147868564).

165721244 is a wasteful number, since it uses less digits than its factorization.

165721244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12965 (or 12963 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 165721244 is about 12873.2763506421. The cubic root of 165721244 is about 549.2786620754.

The spelling of 165721244 in words is "one hundred sixty-five million, seven hundred twenty-one thousand, two hundred forty-four".