644142704 has 10 divisors (see below), whose sum is σ = 1248026520. Its totient is φ = 322071344.

The previous prime is 644142683. The next prime is 644142721. The reversal of 644142704 is 407241446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20129444 + ... + 20129475.

It is an arithmetic number, because the mean of its divisors is an integer number (124802652).

Almost surely, 2^644142704 is an apocalyptic number.

It is an amenable number.

644142704 is a deficient number, since it is larger than the sum of its proper divisors (603883816).

644142704 is a wasteful number, since it uses less digits than its factorization.

644142704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40258927 (or 40258921 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 32.

The square root of 644142704 is about 25379.9665878425. The cubic root of 644142704 is about 863.6292919841.

The spelling of 644142704 in words is "six hundred forty-four million, one hundred forty-two thousand, seven hundred four".