644770084 has 48 divisors (see below), whose sum is σ = 1374710400. Its totient is φ = 258301440.

The previous prime is 644770051. The next prime is 644770211. The reversal of 644770084 is 480077446.

It is a super-2 number, since 2×644770084² = 831456922442734112, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66379 + ... + 75469.

It is an arithmetic number, because the mean of its divisors is an integer number (28639800).

Almost surely, 2^644770084 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 644770084, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687355200).

644770084 is an abundant number, since it is smaller than the sum of its proper divisors (729940316).

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

644770084 is a wasteful number, since it uses less digits than its factorization.

644770084 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9268 (or 9266 counting only the distinct ones).

The product of its (nonzero) digits is 150528, while the sum is 40.

The square root of 644770084 is about 25392.3233281242. The cubic root of 644770084 is about 863.9095859464.

The spelling of 644770084 in words is "six hundred forty-four million, seven hundred seventy thousand, eighty-four".