644492031 has 16 divisors (see below), whose sum is σ = 878691456. Its totient is φ = 420035616.

The previous prime is 644492029. The next prime is 644492053. The reversal of 644492031 is 130294446.

It is not a de Polignac number, because 644492031 - 2¹ = 644492029 is a prime.

It is a super-2 number, since 2×644492031² = 830739956045009922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644491983 and 644492001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644492021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 37836 + ... + 52158.

It is an arithmetic number, because the mean of its divisors is an integer number (54918216).

Almost surely, 2^644492031 is an apocalyptic number.

644492031 is a deficient number, since it is larger than the sum of its proper divisors (234199425).

644492031 is a wasteful number, since it uses less digits than its factorization.

644492031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14662.

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

The square root of 644492031 is about 25386.8475987075. The cubic root of 644492031 is about 863.7853829184.

The spelling of 644492031 in words is "six hundred forty-four million, four hundred ninety-two thousand, thirty-one".