639502947 has 12 divisors (see below), whose sum is σ = 939383640. Its totient is φ = 419108928.

The previous prime is 639502943. The next prime is 639502961. The reversal of 639502947 is 749205936.

It is a happy number.

639502947 is a `hidden beast` number, since 639 + 5 + 0 + 2 + 9 + 4 + 7 = 666.

It is not a de Polignac number, because 639502947 - 2² = 639502943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (639502943) 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 in 11 ways as a sum of consecutive naturals, for example, 601638 + ... + 602699.

It is an arithmetic number, because the mean of its divisors is an integer number (78281970).

Almost surely, 2^639502947 is an apocalyptic number.

639502947 is a deficient number, since it is larger than the sum of its proper divisors (299880693).

639502947 is a wasteful number, since it uses less digits than its factorization.

639502947 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1204402 (or 1204399 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 45.

The square root of 639502947 is about 25288.3955007035. The cubic root of 639502947 is about 861.5507206849.

The spelling of 639502947 in words is "six hundred thirty-nine million, five hundred two thousand, nine hundred forty-seven".