644367249 has 12 divisors (see below), whose sum is σ = 931121412. Its totient is φ = 429408000.

The previous prime is 644367221. The next prime is 644367281. The reversal of 644367249 is 942763446.

It is a happy number.

644367249 is a `hidden beast` number, since 6 + 44 + 367 + 249 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 433972224 + 210395025 = 20832^2 + 14505^2 .

It is not a de Polignac number, because 644367249 - 2¹¹ = 644365201 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640367249) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12429 + ... + 37989.

It is an arithmetic number, because the mean of its divisors is an integer number (77593451).

Almost surely, 2^644367249 is an apocalyptic number.

It is an amenable number.

644367249 is a deficient number, since it is larger than the sum of its proper divisors (286754163).

644367249 is a wasteful number, since it uses less digits than its factorization.

644367249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28368 (or 28365 counting only the distinct ones).

The product of its digits is 870912, while the sum is 45.

The square root of 644367249 is about 25384.3898685787. The cubic root of 644367249 is about 863.7296326430.

The spelling of 644367249 in words is "six hundred forty-four million, three hundred sixty-seven thousand, two hundred forty-nine".