644143104 has 240 divisors, whose sum is σ = 2104862760. Its totient is φ = 194641920.

The previous prime is 644143091. The next prime is 644143133. The reversal of 644143104 is 401341446.

644143104 is a `hidden beast` number, since 644 + 1 + 4 + 3 + 10 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1824592 + ... + 1824944.

Almost surely, 2^644143104 is an apocalyptic number.

644143104 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644143104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1052431380).

644143104 is an abundant number, since it is smaller than the sum of its proper divisors (1460719656).

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

644143104 is a wasteful number, since it uses less digits than its factorization.

644143104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 369 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 27.

The square root of 644143104 is about 25379.9744680723. The cubic root of 644143104 is about 863.6294707497.

The spelling of 644143104 in words is "six hundred forty-four million, one hundred forty-three thousand, one hundred four".