21637764064 has 48 divisors (see below), whose sum is σ = 48700020096. Its totient is φ = 9270460800.

The previous prime is 21637764041. The next prime is 21637764077. The reversal of 21637764064 is 46046773612.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 813699 + ... + 839869.

It is an arithmetic number, because the mean of its divisors is an integer number (1014583752).

Almost surely, 2^21637764064 is an apocalyptic number.

It is an amenable number.

21637764064 is an abundant number, since it is smaller than the sum of its proper divisors (27062256032).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21637764064 is a wasteful number, since it uses less digits than its factorization.

21637764064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29879 (or 29871 counting only the distinct ones).

The product of its (nonzero) digits is 1016064, while the sum is 46.

The spelling of 21637764064 in words is "twenty-one billion, six hundred thirty-seven million, seven hundred sixty-four thousand, sixty-four".