21207584815 has 32 divisors (see below), whose sum is σ = 26871223680. Its totient is φ = 16036061184.

The previous prime is 21207584737. The next prime is 21207584819. The reversal of 21207584815 is 51848570212.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21207584815 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21207584819) 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 31 ways as a sum of consecutive naturals, for example, 10451221 + ... + 10453249.

It is an arithmetic number, because the mean of its divisors is an integer number (839725740).

Almost surely, 2^21207584815 is an apocalyptic number.

21207584815 is a deficient number, since it is larger than the sum of its proper divisors (5663638865).

21207584815 is a wasteful number, since it uses less digits than its factorization.

21207584815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3091.

The product of its (nonzero) digits is 179200, while the sum is 43.

The spelling of 21207584815 in words is "twenty-one billion, two hundred seven million, five hundred eighty-four thousand, eight hundred fifteen".