639813617 has 2 divisors, whose sum is σ = 639813618. Its totient is φ = 639813616.

The previous prime is 639813611. The next prime is 639813659. The reversal of 639813617 is 716318936.

639813617 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 581581456 + 58232161 = 24116^2 + 7631^2 .

It is a cyclic number.

It is not a de Polignac number, because 639813617 - 2⁶ = 639813553 is a prime.

It is a super-2 number, since 2×639813617² = 818722928997245378, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (639813611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319906808 + 319906809.

It is an arithmetic number, because the mean of its divisors is an integer number (319906809).

Almost surely, 2^639813617 is an apocalyptic number.

It is an amenable number.

639813617 is a deficient number, since it is larger than the sum of its proper divisors (1).

639813617 is an equidigital number, since it uses as much as digits as its factorization.

639813617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 44.

The square root of 639813617 is about 25294.5372956297. The cubic root of 639813617 is about 861.6902116404.

The spelling of 639813617 in words is "six hundred thirty-nine million, eight hundred thirteen thousand, six hundred seventeen".