644024024 has 16 divisors (see below), whose sum is σ = 1380051600. Its totient is φ = 276010272.

The previous prime is 644023987. The next prime is 644024027. The reversal of 644024024 is 420420446.

It is a junction number, because it is equal to n+sod(n) for n = 644023984 and 644024002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644024027) 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 3 ways as a sum of consecutive naturals, for example, 5750159 + ... + 5750270.

It is an arithmetic number, because the mean of its divisors is an integer number (86253225).

Almost surely, 2^644024024 is an apocalyptic number.

It is an amenable number.

644024024 is an abundant number, since it is smaller than the sum of its proper divisors (736027576).

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

644024024 is a wasteful number, since it uses less digits than its factorization.

644024024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11500442 (or 11500438 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 26.

The square root of 644024024 is about 25377.6284155947. The cubic root of 644024024 is about 863.5762489657.

The spelling of 644024024 in words is "six hundred forty-four million, twenty-four thousand, twenty-four".