644768370 has 32 divisors (see below), whose sum is σ = 1719383040. Its totient is φ = 171938160.

The previous prime is 644768357. The next prime is 644768387. The reversal of 644768370 is 73867446.

644768370 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 1193746 + ... + 1194285.

It is an arithmetic number, because the mean of its divisors is an integer number (53730720).

Almost surely, 2^644768370 is an apocalyptic number.

644768370 is an abundant number, since it is smaller than the sum of its proper divisors (1074614670).

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

644768370 is a wasteful number, since it uses less digits than its factorization.

644768370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2388047 (or 2388041 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 45.

The square root of 644768370 is about 25392.2895777439. The cubic root of 644768370 is about 863.9088204320.

The spelling of 644768370 in words is "six hundred forty-four million, seven hundred sixty-eight thousand, three hundred seventy".