639372847 has 2 divisors, whose sum is σ = 639372848. Its totient is φ = 639372846.

The previous prime is 639372827. The next prime is 639372859. The reversal of 639372847 is 748273936.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639372847 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 639372847.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639372817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319686423 + 319686424.

It is an arithmetic number, because the mean of its divisors is an integer number (319686424).

Almost surely, 2^639372847 is an apocalyptic number.

639372847 is a deficient number, since it is larger than the sum of its proper divisors (1).

639372847 is an equidigital number, since it uses as much as digits as its factorization.

639372847 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1524096, while the sum is 49.

The square root of 639372847 is about 25285.8230437532. The cubic root of 639372847 is about 861.4922923116.

The spelling of 639372847 in words is "six hundred thirty-nine million, three hundred seventy-two thousand, eight hundred forty-seven".