638660463667 has 2 divisors, whose sum is σ = 638660463668. Its totient is φ = 638660463666.

The previous prime is 638660463613. The next prime is 638660463677. The reversal of 638660463667 is 766364066836.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 638660463667 - 2²³ = 638652075059 is a prime.

It is not a weakly prime, because it can be changed into another prime (638660463677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319330231833 + 319330231834.

It is an arithmetic number, because the mean of its divisors is an integer number (319330231834).

Almost surely, 2^638660463667 is an apocalyptic number.

638660463667 is a deficient number, since it is larger than the sum of its proper divisors (1).

638660463667 is an equidigital number, since it uses as much as digits as its factorization.

638660463667 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 94058496, while the sum is 61.

The spelling of 638660463667 in words is "six hundred thirty-eight billion, six hundred sixty million, four hundred sixty-three thousand, six hundred sixty-seven".