667340538021 has 16 divisors (see below), whose sum is σ = 990190237120. Its totient is φ = 444201777360.

The previous prime is 667340537989. The next prime is 667340538041. The reversal of 667340538021 is 120835043766.

667340538021 is a `hidden beast` number, since 6 + 6 + 73 + 40 + 538 + 0 + 2 + 1 = 666.

It is not a de Polignac number, because 667340538021 - 2⁵ = 667340537989 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 (667340538041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19202170 + ... + 19236891.

It is an arithmetic number, because the mean of its divisors is an integer number (61886889820).

Almost surely, 2^667340538021 is an apocalyptic number.

It is an amenable number.

667340538021 is a deficient number, since it is larger than the sum of its proper divisors (322849699099).

667340538021 is a wasteful number, since it uses less digits than its factorization.

667340538021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38439713 (or 38439707 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 45.

The spelling of 667340538021 in words is "six hundred sixty-seven billion, three hundred forty million, five hundred thirty-eight thousand, twenty-one".