644652423 has 24 divisors (see below), whose sum is σ = 959931648. Its totient is φ = 416663952.

The previous prime is 644652413. The next prime is 644652439. The reversal of 644652423 is 324256446.

644652423 is a `hidden beast` number, since 644 + 6 + 5 + 2 + 4 + 2 + 3 = 666.

It is not a de Polignac number, because 644652423 - 2⁵ = 644652391 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644652413) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38140 + ... + 52382.

It is an arithmetic number, because the mean of its divisors is an integer number (39997152).

Almost surely, 2^644652423 is an apocalyptic number.

644652423 is a deficient number, since it is larger than the sum of its proper divisors (315279225).

644652423 is a wasteful number, since it uses less digits than its factorization.

644652423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14403 (or 14400 counting only the distinct ones).

The product of its digits is 138240, while the sum is 36.

The square root of 644652423 is about 25390.0063607712. The cubic root of 644652423 is about 863.8570325107.

The spelling of 644652423 in words is "six hundred forty-four million, six hundred fifty-two thousand, four hundred twenty-three".