644130396 has 144 divisors (see below), whose sum is σ = 2013246144. Its totient is φ = 169095168.

The previous prime is 644130349. The next prime is 644130413. The reversal of 644130396 is 693031446.

644130396 is a `hidden beast` number, since 644 + 1 + 3 + 0 + 3 + 9 + 6 = 666.

It is a super-2 number, since 2×644130396² = 829807934102233632, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 644130396.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1156150 + ... + 1156706.

It is an arithmetic number, because the mean of its divisors is an integer number (13980876).

Almost surely, 2^644130396 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644130396, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1006623072).

644130396 is an abundant number, since it is smaller than the sum of its proper divisors (1369115748).

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

644130396 is a wasteful number, since it uses less digits than its factorization.

644130396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 940 (or 935 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 644130396 is about 25379.7241119757. The cubic root of 644130396 is about 863.6237913308.

The spelling of 644130396 in words is "six hundred forty-four million, one hundred thirty thousand, three hundred ninety-six".