644216370 has 64 divisors (see below), whose sum is σ = 1791922176. Its totient is φ = 145172160.

The previous prime is 644216347. The next prime is 644216371. The reversal of 644216370 is 73612446.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (644216371) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6694 + ... + 36513.

It is an arithmetic number, because the mean of its divisors is an integer number (27998784).

Almost surely, 2^644216370 is an apocalyptic number.

644216370 is an abundant number, since it is smaller than the sum of its proper divisors (1147705806).

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

644216370 is a wasteful number, since it uses less digits than its factorization.

644216370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43295.

The product of its (nonzero) digits is 24192, while the sum is 33.

The square root of 644216370 is about 25381.4178090981. The cubic root of 644216370 is about 863.6622131002.

The spelling of 644216370 in words is "six hundred forty-four million, two hundred sixteen thousand, three hundred seventy".