664651252620021 has 8 divisors (see below), whose sum is σ = 886944504758400. Its totient is φ = 442729417780832.

The previous prime is 664651252619989. The next prime is 664651252620049. The reversal of 664651252620021 is 120026252156466.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 664651252620021 - 2⁵ = 664651252619989 is a prime.

It is a super-2 number, since 2×664651252620021² (a number of 30 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664651252625021) 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, 92854320621 + ... + 92854327778.

It is an arithmetic number, because the mean of its divisors is an integer number (110868063094800).

Almost surely, 2^{664651252620021} is an apocalyptic number.

It is an amenable number.

664651252620021 is a deficient number, since it is larger than the sum of its proper divisors (222293252138379).

664651252620021 is a wasteful number, since it uses less digits than its factorization.

664651252620021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185708649595.

The product of its (nonzero) digits is 2073600, while the sum is 48.

The spelling of 664651252620021 in words is "six hundred sixty-four trillion, six hundred fifty-one billion, two hundred fifty-two million, six hundred twenty thousand, twenty-one".