664427731626 has 12 divisors (see below), whose sum is σ = 1439593418562. Its totient is φ = 221475910536.

The previous prime is 664427731601. The next prime is 664427731711. The reversal of 664427731626 is 626137724466.

664427731626 is a `hidden beast` number, since 6 + 6 + 4 + 4 + 2 + 7 + 7 + 3 + 1 + 626 = 666.

It can be written as a sum of positive squares in only one way, i.e., 385063686225 + 279364045401 = 620535^2 + 528549^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18456325861 + ... + 18456325896.

Almost surely, 2^664427731626 is an apocalyptic number.

664427731626 is an abundant number, since it is smaller than the sum of its proper divisors (775165686936).

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

664427731626 is a wasteful number, since it uses less digits than its factorization.

664427731626 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36912651765 (or 36912651762 counting only the distinct ones).

The product of its digits is 12192768, while the sum is 54.

The spelling of 664427731626 in words is "six hundred sixty-four billion, four hundred twenty-seven million, seven hundred thirty-one thousand, six hundred twenty-six".