21620512 has 24 divisors (see below), whose sum is σ = 42676956. Its totient is φ = 10781952.

The previous prime is 21620509. The next prime is 21620513. The reversal of 21620512 is 21502612.

It can be written as a sum of positive squares in 2 ways, for example, as 16032016 + 5588496 = 4004^2 + 2364^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21620512.

It is not an unprimeable number, because it can be changed into a prime (21620513) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17218 + ... + 18430.

Almost surely, 2^21620512 is an apocalyptic number.

It is an amenable number.

21620512 is a deficient number, since it is larger than the sum of its proper divisors (21056444).

21620512 is a wasteful number, since it uses less digits than its factorization.

21620512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1780 (or 1772 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21620512 is about 4649.7862316455. The cubic root of 21620512 is about 278.5834579321.

The spelling of 21620512 in words is "twenty-one million, six hundred twenty thousand, five hundred twelve".