21217805624 has 32 divisors (see below), whose sum is σ = 41622768000. Its totient is φ = 10120838112.

The previous prime is 21217805599. The next prime is 21217805627. The reversal of 21217805624 is 42650871212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21217805627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 82394 + ... + 221865.

It is an arithmetic number, because the mean of its divisors is an integer number (1300711500).

Almost surely, 2^21217805624 is an apocalyptic number.

It is an amenable number.

21217805624 is a deficient number, since it is larger than the sum of its proper divisors (20404962376).

21217805624 is a wasteful number, since it uses less digits than its factorization.

21217805624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304667 (or 304663 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 38.

The spelling of 21217805624 in words is "twenty-one billion, two hundred seventeen million, eight hundred five thousand, six hundred twenty-four".