644834696256 has 315 divisors, whose sum is σ = 2020834522839. Its totient is φ = 203285106432.

The previous prime is 644834696213. The next prime is 644834696269. The reversal of 644834696256 is 652696438446.

The square root of 644834696256 is 803016.

It is a perfect power (a square), and thus also a powerful number.

644834696256 is a `hidden beast` number, since 6 + 4 + 483 + 46 + 9 + 62 + 56 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 644834696193 and 644834696202.

It is an unprimeable number.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1098525595 + ... + 1098526181.

Almost surely, 2^644834696256 is an apocalyptic number.

644834696256 is the 803016-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644834696256

644834696256 is an abundant number, since it is smaller than the sum of its proper divisors (1375999826583).

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

644834696256 is an frugal number, since it uses more digits than its factorization.

644834696256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1236 (or 611 counting only the distinct ones).

The product of its digits is 179159040, while the sum is 63.

The spelling of 644834696256 in words is "six hundred forty-four billion, eight hundred thirty-four million, six hundred ninety-six thousand, two hundred fifty-six".