667764478639 has 2 divisors, whose sum is σ = 667764478640. Its totient is φ = 667764478638.

The previous prime is 667764478609. The next prime is 667764478691. The reversal of 667764478639 is 936874467766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 667764478639 - 2²⁷ = 667630260911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667764478609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333882239319 + 333882239320.

It is an arithmetic number, because the mean of its divisors is an integer number (333882239320).

Almost surely, 2^667764478639 is an apocalyptic number.

667764478639 is a deficient number, since it is larger than the sum of its proper divisors (1).

667764478639 is an equidigital number, since it uses as much as digits as its factorization.

667764478639 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1536288768, while the sum is 73.

The spelling of 667764478639 in words is "six hundred sixty-seven billion, seven hundred sixty-four million, four hundred seventy-eight thousand, six hundred thirty-nine".