639108817 has 2 divisors, whose sum is σ = 639108818. Its totient is φ = 639108816.

The previous prime is 639108793. The next prime is 639108851. The reversal of 639108817 is 718801936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 492795601 + 146313216 = 22199^2 + 12096^2 .

It is a cyclic number.

It is not a de Polignac number, because 639108817 - 2⁷ = 639108689 is a prime.

It is not a weakly prime, because it can be changed into another prime (639108017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319554408 + 319554409.

It is an arithmetic number, because the mean of its divisors is an integer number (319554409).

Almost surely, 2^639108817 is an apocalyptic number.

It is an amenable number.

639108817 is a deficient number, since it is larger than the sum of its proper divisors (1).

639108817 is an equidigital number, since it uses as much as digits as its factorization.

639108817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72576, while the sum is 43.

The square root of 639108817 is about 25280.6015948988. The cubic root of 639108817 is about 861.3736911291.

It can be divided in two parts, 63910 and 8817, that added together give a palindrome (72727).

The spelling of 639108817 in words is "six hundred thirty-nine million, one hundred eight thousand, eight hundred seventeen".