667645504365639 has 32 divisors (see below), whose sum is σ = 894300895724544. Its totient is φ = 443048201164800.

The previous prime is 667645504365613. The next prime is 667645504365677. The reversal of 667645504365639 is 936563405546766.

It is not a de Polignac number, because 667645504365639 - 2¹² = 667645504361543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667645504365239) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6228970642 + ... + 6229077824.

It is an arithmetic number, because the mean of its divisors is an integer number (27946902991392).

Almost surely, 2^{667645504365639} is an apocalyptic number.

667645504365639 is a deficient number, since it is larger than the sum of its proper divisors (226655391358905).

667645504365639 is a wasteful number, since it uses less digits than its factorization.

667645504365639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117927.

The product of its (nonzero) digits is 8817984000, while the sum is 75.

The spelling of 667645504365639 in words is "six hundred sixty-seven trillion, six hundred forty-five billion, five hundred four million, three hundred sixty-five thousand, six hundred thirty-nine".