165213643 has 12 divisors (see below), whose sum is σ = 193597992. Its totient is φ = 140572320.

The previous prime is 165213563. The next prime is 165213647. The reversal of 165213643 is 346312561.

It is not a de Polignac number, because 165213643 - 2²⁵ = 131659211 is a prime.

It is not an unprimeable number, because it can be changed into a prime (165213647) 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 11 ways as a sum of consecutive naturals, for example, 5593 + ... + 19018.

It is an arithmetic number, because the mean of its divisors is an integer number (16133166).

Almost surely, 2^165213643 is an apocalyptic number.

165213643 is a deficient number, since it is larger than the sum of its proper divisors (28384349).

165213643 is a wasteful number, since it uses less digits than its factorization.

165213643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24762 (or 24755 counting only the distinct ones).

The product of its digits is 12960, while the sum is 31.

The square root of 165213643 is about 12853.5459309873. The cubic root of 165213643 is about 548.7172785044.

It can be divided in two parts, 16521 and 3643, that added together give a square (20164 = 142²).

The spelling of 165213643 in words is "one hundred sixty-five million, two hundred thirteen thousand, six hundred forty-three".