639967117 has 2 divisors, whose sum is σ = 639967118. Its totient is φ = 639967116.

The previous prime is 639967079. The next prime is 639967127. The reversal of 639967117 is 711769936.

639967117 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 532409476 + 107557641 = 23074^2 + 10371^2 .

It is a cyclic number.

It is not a de Polignac number, because 639967117 - 2¹⁹ = 639442829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639967127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319983558 + 319983559.

It is an arithmetic number, because the mean of its divisors is an integer number (319983559).

Almost surely, 2^639967117 is an apocalyptic number.

It is an amenable number.

639967117 is a deficient number, since it is larger than the sum of its proper divisors (1).

639967117 is an equidigital number, since it uses as much as digits as its factorization.

639967117 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 428652, while the sum is 49.

The square root of 639967117 is about 25297.5713656469. The cubic root of 639967117 is about 861.7591165358.

The spelling of 639967117 in words is "six hundred thirty-nine million, nine hundred sixty-seven thousand, one hundred seventeen".