21064542664 has 32 divisors (see below), whose sum is σ = 43169358240. Its totient is φ = 9556393600.

The previous prime is 21064542623. The next prime is 21064542739. The reversal of 21064542664 is 46624546012.

It is a happy 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, 183874 + ... + 275569.

It is an arithmetic number, because the mean of its divisors is an integer number (1349042445).

Almost surely, 2^21064542664 is an apocalyptic number.

It is an amenable number.

21064542664 is an abundant number, since it is smaller than the sum of its proper divisors (22104815576).

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

21064542664 is a wasteful number, since it uses less digits than its factorization.

21064542664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459981 (or 459977 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 40.

The spelling of 21064542664 in words is "twenty-one billion, sixty-four million, five hundred forty-two thousand, six hundred sixty-four".