644713776 has 320 divisors, whose sum is σ = 2281600000. Its totient is φ = 173746944.

The previous prime is 644713723. The next prime is 644713777. The reversal of 644713776 is 677317446.

644713776 is a `hidden beast` number, since 6 + 447 + 137 + 76 = 666.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (644713777) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2815230 + ... + 2815458.

It is an arithmetic number, because the mean of its divisors is an integer number (7130000).

Almost surely, 2^644713776 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 644713776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1140800000).

644713776 is an abundant number, since it is smaller than the sum of its proper divisors (1636886224).

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

644713776 is a wasteful number, since it uses less digits than its factorization.

644713776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 286 (or 260 counting only the distinct ones).

The product of its digits is 592704, while the sum is 45.

The square root of 644713776 is about 25391.2145436172. The cubic root of 644713776 is about 863.8844367042.

The spelling of 644713776 in words is "six hundred forty-four million, seven hundred thirteen thousand, seven hundred seventy-six".