644269392 has 60 divisors (see below), whose sum is σ = 1941762004. Its totient is φ = 198236160.

The previous prime is 644269361. The next prime is 644269393. The reversal of 644269392 is 293962446.

It can be written as a sum of positive squares in 2 ways, for example, as 400160016 + 244109376 = 20004^2 + 15624^2 .

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644269393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 170209 + ... + 173952.

Almost surely, 2^644269392 is an apocalyptic number.

It is an amenable number.

644269392 is an abundant number, since it is smaller than the sum of its proper divisors (1297492612).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

644269392 is a wasteful number, since it uses less digits than its factorization.

644269392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 344188 (or 344179 counting only the distinct ones).

The product of its digits is 559872, while the sum is 45.

The square root of 644269392 is about 25382.4622919054. The cubic root of 644269392 is about 863.6859069210.

The spelling of 644269392 in words is "six hundred forty-four million, two hundred sixty-nine thousand, three hundred ninety-two".