640599667 has 2 divisors, whose sum is σ = 640599668. Its totient is φ = 640599666.

The previous prime is 640599653. The next prime is 640599677. The reversal of 640599667 is 766995046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640599667 - 2¹¹ = 640597619 is a prime.

It is not a weakly prime, because it can be changed into another prime (640599677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320299833 + 320299834.

It is an arithmetic number, because the mean of its divisors is an integer number (320299834).

Almost surely, 2^640599667 is an apocalyptic number.

640599667 is a deficient number, since it is larger than the sum of its proper divisors (1).

640599667 is an equidigital number, since it uses as much as digits as its factorization.

640599667 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2449440, while the sum is 52.

The square root of 640599667 is about 25310.0704661208. The cubic root of 640599667 is about 862.0429468646.

The spelling of 640599667 in words is "six hundred forty million, five hundred ninety-nine thousand, six hundred sixty-seven".