644819292 has 120 divisors (see below), whose sum is σ = 1878307200. Its totient is φ = 191528064.

The previous prime is 644819233. The next prime is 644819311. The reversal of 644819292 is 292918446.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 119509 + ... + 124787.

It is an arithmetic number, because the mean of its divisors is an integer number (15652560).

Almost surely, 2^644819292 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 644819292, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (939153600).

644819292 is an abundant number, since it is smaller than the sum of its proper divisors (1233487908).

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

644819292 is a wasteful number, since it uses less digits than its factorization.

644819292 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5337 (or 5326 counting only the distinct ones).

The product of its digits is 248832, while the sum is 45.

The square root of 644819292 is about 25393.2922639031. The cubic root of 644819292 is about 863.9315628663.

The spelling of 644819292 in words is "six hundred forty-four million, eight hundred nineteen thousand, two hundred ninety-two".