639676291 has 2 divisors, whose sum is σ = 639676292. Its totient is φ = 639676290.

The previous prime is 639676283. The next prime is 639676309. The reversal of 639676291 is 192676936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639676291 - 2³ = 639676283 is a prime.

It is not a weakly prime, because it can be changed into another prime (639673291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319838145 + 319838146.

It is an arithmetic number, because the mean of its divisors is an integer number (319838146).

Almost surely, 2^639676291 is an apocalyptic number.

639676291 is a deficient number, since it is larger than the sum of its proper divisors (1).

639676291 is an equidigital number, since it uses as much as digits as its factorization.

639676291 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 734832, while the sum is 49.

The square root of 639676291 is about 25291.8226112710. The cubic root of 639676291 is about 861.6285577806.

The spelling of 639676291 in words is "six hundred thirty-nine million, six hundred seventy-six thousand, two hundred ninety-one".