644074038 has 64 divisors (see below), whose sum is σ = 1479329280. Its totient is φ = 207585504.

The previous prime is 644074009. The next prime is 644074049. The reversal of 644074038 is 830470446.

644074038 is a `hidden beast` number, since 644 + 0 + 7 + 4 + 0 + 3 + 8 = 666.

644074038 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644073993 and 644074011.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 237820 + ... + 240512.

It is an arithmetic number, because the mean of its divisors is an integer number (23114520).

Almost surely, 2^644074038 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644074038, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (739664640).

644074038 is an abundant number, since it is smaller than the sum of its proper divisors (835255242).

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

644074038 is a wasteful number, since it uses less digits than its factorization.

644074038 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2850 (or 2844 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 36.

The square root of 644074038 is about 25378.6137919312. The cubic root of 644074038 is about 863.5986030928.

The spelling of 644074038 in words is "six hundred forty-four million, seventy-four thousand, thirty-eight".