639722943 has 12 divisors (see below), whose sum is σ = 964220400. Its totient is φ = 407939136.

The previous prime is 639722939. The next prime is 639722953. The reversal of 639722943 is 349227936.

639722943 is a `hidden beast` number, since 639 + 7 + 2 + 2 + 9 + 4 + 3 = 666.

It is not a de Polignac number, because 639722943 - 2² = 639722939 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639722953) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1545018 + ... + 1545431.

It is an arithmetic number, because the mean of its divisors is an integer number (80351700).

Almost surely, 2^639722943 is an apocalyptic number.

639722943 is a deficient number, since it is larger than the sum of its proper divisors (324497457).

639722943 is a wasteful number, since it uses less digits than its factorization.

639722943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3090478 (or 3090475 counting only the distinct ones).

The product of its digits is 489888, while the sum is 45.

The square root of 639722943 is about 25292.7448688354. The cubic root of 639722943 is about 861.6495036449.

The spelling of 639722943 in words is "six hundred thirty-nine million, seven hundred twenty-two thousand, nine hundred forty-three".