639655513 has 4 divisors (see below), whose sum is σ = 731034880. Its totient is φ = 548276148.

The previous prime is 639655483. The next prime is 639655517. The reversal of 639655513 is 315556936.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-639655513 is a prime.

It is a super-2 number, since 2×639655513² = 818318350622586338, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 639655513.

It is not an unprimeable number, because it can be changed into a prime (639655517) 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 3 ways as a sum of consecutive naturals, for example, 45689673 + ... + 45689686.

It is an arithmetic number, because the mean of its divisors is an integer number (182758720).

Almost surely, 2^639655513 is an apocalyptic number.

It is an amenable number.

639655513 is a deficient number, since it is larger than the sum of its proper divisors (91379367).

639655513 is an equidigital number, since it uses as much as digits as its factorization.

639655513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91379366.

The product of its digits is 364500, while the sum is 43.

The square root of 639655513 is about 25291.4118427580. The cubic root of 639655513 is about 861.6192285244.

The spelling of 639655513 in words is "six hundred thirty-nine million, six hundred fifty-five thousand, five hundred thirteen".