639664044127 has 2 divisors, whose sum is σ = 639664044128. Its totient is φ = 639664044126.

The previous prime is 639664044073. The next prime is 639664044167. The reversal of 639664044127 is 721440466936.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 639664044127 - 2¹¹ = 639664042079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639664044167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319832022063 + 319832022064.

It is an arithmetic number, because the mean of its divisors is an integer number (319832022064).

Almost surely, 2^639664044127 is an apocalyptic number.

639664044127 is a deficient number, since it is larger than the sum of its proper divisors (1).

639664044127 is an equidigital number, since it uses as much as digits as its factorization.

639664044127 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5225472, while the sum is 52.

The spelling of 639664044127 in words is "six hundred thirty-nine billion, six hundred sixty-four million, forty-four thousand, one hundred twenty-seven".