664616664612 has 18 divisors (see below), whose sum is σ = 1680003235638. Its totient is φ = 221538888192.

The previous prime is 664616664599. The next prime is 664616664643. The reversal of 664616664612 is 216466616466.

It can be written as a sum of positive squares in only one way, i.e., 662687171136 + 1929493476 = 814056^2 + 43926^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×664616664612² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9230786973 + ... + 9230787044.

It is an arithmetic number, because the mean of its divisors is an integer number (93333513091).

Almost surely, 2^664616664612 is an apocalyptic number.

It is an amenable number.

664616664612 is an abundant number, since it is smaller than the sum of its proper divisors (1015386571026).

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

664616664612 is a wasteful number, since it uses less digits than its factorization.

664616664612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18461574027 (or 18461574022 counting only the distinct ones).

The product of its digits is 8957952, while the sum is 54.

The spelling of 664616664612 in words is "six hundred sixty-four billion, six hundred sixteen million, six hundred sixty-four thousand, six hundred twelve".