639031369 has 2 divisors, whose sum is σ = 639031370. Its totient is φ = 639031368.

The previous prime is 639031363. The next prime is 639031397. The reversal of 639031369 is 963130936.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 637310025 + 1721344 = 25245^2 + 1312^2 .

It is a cyclic number.

It is not a de Polignac number, because 639031369 - 2²¹ = 636934217 is a prime.

It is a super-2 number, since 2×639031369² = 816722181132028322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (639031363) 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, 319515684 + 319515685.

It is an arithmetic number, because the mean of its divisors is an integer number (319515685).

Almost surely, 2^639031369 is an apocalyptic number.

It is an amenable number.

639031369 is a deficient number, since it is larger than the sum of its proper divisors (1).

639031369 is an equidigital number, since it uses as much as digits as its factorization.

639031369 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 78732, while the sum is 40.

The square root of 639031369 is about 25279.0697811450. The cubic root of 639031369 is about 861.3388956124.

The spelling of 639031369 in words is "six hundred thirty-nine million, thirty-one thousand, three hundred sixty-nine".