644662532 has 12 divisors (see below), whose sum is σ = 1149445836. Its totient is φ = 316249440.

The previous prime is 644662523. The next prime is 644662537. The reversal of 644662532 is 235266446.

It can be written as a sum of positive squares in 2 ways, for example, as 544942336 + 99720196 = 23344^2 + 9986^2 .

It is not an unprimeable number, because it can be changed into a prime (644662537) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1520219 + ... + 1520642.

It is an arithmetic number, because the mean of its divisors is an integer number (95787153).

Almost surely, 2^644662532 is an apocalyptic number.

It is an amenable number.

644662532 is a deficient number, since it is larger than the sum of its proper divisors (504783304).

644662532 is a wasteful number, since it uses less digits than its factorization.

644662532 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3040918 (or 3040916 counting only the distinct ones).

The product of its digits is 207360, while the sum is 38.

The square root of 644662532 is about 25390.2054343796. The cubic root of 644662532 is about 863.8615479595.

The spelling of 644662532 in words is "six hundred forty-four million, six hundred sixty-two thousand, five hundred thirty-two".