644742633 has 8 divisors (see below), whose sum is σ = 860040288. Its totient is φ = 429636704.

The previous prime is 644742613. The next prime is 644742661. The reversal of 644742633 is 336247446.

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

It is a cyclic number.

It is not a de Polignac number, because 644742633 - 2⁸ = 644742377 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 644742591 and 644742600.

It is not an unprimeable number, because it can be changed into a prime (644742613) 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, 39891 + ... + 53672.

It is an arithmetic number, because the mean of its divisors is an integer number (107505036).

Almost surely, 2^644742633 is an apocalyptic number.

It is an amenable number.

644742633 is a deficient number, since it is larger than the sum of its proper divisors (215297655).

644742633 is a wasteful number, since it uses less digits than its factorization.

644742633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95863.

The product of its digits is 290304, while the sum is 39.

The square root of 644742633 is about 25391.7827849877. The cubic root of 644742633 is about 863.8973254941.

The spelling of 644742633 in words is "six hundred forty-four million, seven hundred forty-two thousand, six hundred thirty-three".