664064021 has 8 divisors (see below), whose sum is σ = 673965600. Its totient is φ = 654235920.

The previous prime is 664063943. The next prime is 664064033. The reversal of 664064021 is 120460466.

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 664064021 - 2¹⁸ = 663801877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664064521) by changing a digit.

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, 26 + ... + 36443.

It is an arithmetic number, because the mean of its divisors is an integer number (84245700).

Almost surely, 2^664064021 is an apocalyptic number.

It is an amenable number.

664064021 is a deficient number, since it is larger than the sum of its proper divisors (9901579).

664064021 is a wasteful number, since it uses less digits than its factorization.

664064021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36739.

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 664064021 is about 25769.4396718283. The cubic root of 664064021 is about 872.4421719568.

The spelling of 664064021 in words is "six hundred sixty-four million, sixty-four thousand, twenty-one".