644626131 has 8 divisors (see below), whose sum is σ = 860993424. Its totient is φ = 429004800.

The previous prime is 644626063. The next prime is 644626133. The reversal of 644626131 is 131626446.

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

It is not a de Polignac number, because 644626131 - 2¹⁵ = 644593363 is a prime.

It is a super-2 number, since 2×644626131² = 831085697536058322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644626092 and 644626101.

It is not an unprimeable number, because it can be changed into a prime (644626133) 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, 184470 + ... + 187931.

It is an arithmetic number, because the mean of its divisors is an integer number (107624178).

Almost surely, 2^644626131 is an apocalyptic number.

644626131 is a deficient number, since it is larger than the sum of its proper divisors (216367293).

644626131 is a wasteful number, since it uses less digits than its factorization.

644626131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372981.

The product of its digits is 20736, while the sum is 33.

The square root of 644626131 is about 25389.4885927228. The cubic root of 644626131 is about 863.8452882812.

The spelling of 644626131 in words is "six hundred forty-four million, six hundred twenty-six thousand, one hundred thirty-one".