639965031 has 8 divisors (see below), whose sum is σ = 853885440. Its totient is φ = 426343992.

The previous prime is 639965009. The next prime is 639965077. The reversal of 639965031 is 130569936.

639965031 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 639965031 - 2⁹ = 639964519 is a prime.

It is a super-2 number, since 2×639965031² = 819110481805661922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639765031) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69805 + ... + 78438.

It is an arithmetic number, because the mean of its divisors is an integer number (106735680).

Almost surely, 2^639965031 is an apocalyptic number.

639965031 is a deficient number, since it is larger than the sum of its proper divisors (213920409).

639965031 is a wasteful number, since it uses less digits than its factorization.

639965031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149685.

The product of its (nonzero) digits is 131220, while the sum is 42.

The square root of 639965031 is about 25297.5301363592. The cubic root of 639965031 is about 861.7581802213.

The spelling of 639965031 in words is "six hundred thirty-nine million, nine hundred sixty-five thousand, thirty-one".