21307760664 has 32 divisors (see below), whose sum is σ = 53911206720. Its totient is φ = 7017012896.

The previous prime is 21307760641. The next prime is 21307760699. The reversal of 21307760664 is 46606770312.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5346342 + ... + 5350325.

It is an arithmetic number, because the mean of its divisors is an integer number (1684725210).

Almost surely, 2^21307760664 is an apocalyptic number.

21307760664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21307760664 is an abundant number, since it is smaller than the sum of its proper divisors (32603446056).

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

21307760664 is a wasteful number, since it uses less digits than its factorization.

21307760664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10696759 (or 10696755 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 42.

The spelling of 21307760664 in words is "twenty-one billion, three hundred seven million, seven hundred sixty thousand, six hundred sixty-four".