21626564817 has 32 divisors (see below), whose sum is σ = 33891580800. Its totient is φ = 12093419520.

The previous prime is 21626564803. The next prime is 21626564833. The reversal of 21626564817 is 71846562612.

It is not a de Polignac number, because 21626564817 - 2¹⁸ = 21626302673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21626564837) 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, 1083633 + ... + 1103409.

It is an arithmetic number, because the mean of its divisors is an integer number (1059111900).

Almost surely, 2^21626564817 is an apocalyptic number.

It is an amenable number.

21626564817 is a deficient number, since it is larger than the sum of its proper divisors (12265015983).

21626564817 is a wasteful number, since it uses less digits than its factorization.

21626564817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22353.

The product of its digits is 967680, while the sum is 48.

The spelling of 21626564817 in words is "twenty-one billion, six hundred twenty-six million, five hundred sixty-four thousand, eight hundred seventeen".