644692232 has 36 divisors (see below), whose sum is σ = 1241564415. Its totient is φ = 313835920.

The previous prime is 644692199. The next prime is 644692261. The reversal of 644692232 is 232296446.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 322346116 + 322346116 = 17954^2 + 17954^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=17954.

It is a super-3 number, since 3×644692232³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is an unprimeable number.

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 8 ways as a sum of consecutive naturals, for example, 3375257 + ... + 3375447.

Almost surely, 2^644692232 is an apocalyptic number.

It is an amenable number.

644692232 is a deficient number, since it is larger than the sum of its proper divisors (596872183).

644692232 is an equidigital number, since it uses as much as digits as its factorization.

644692232 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 482 (or 240 counting only the distinct ones).

The product of its digits is 124416, while the sum is 38.

The square root of 644692232 is about 25390.7902988465. The cubic root of 644692232 is about 863.8748139670.

The spelling of 644692232 in words is "six hundred forty-four million, six hundred ninety-two thousand, two hundred thirty-two".