644090610 has 64 divisors (see below), whose sum is σ = 1582156800. Its totient is φ = 167758272.

The previous prime is 644090599. The next prime is 644090639. The reversal of 644090610 is 16090446.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 294501 + ... + 296679.

It is an arithmetic number, because the mean of its divisors is an integer number (24721200).

Almost surely, 2^644090610 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644090610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (791078400).

644090610 is an abundant number, since it is smaller than the sum of its proper divisors (938066190).

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

644090610 is a wasteful number, since it uses less digits than its factorization.

644090610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2415.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 644090610 is about 25378.9402852050. The cubic root of 644090610 is about 863.6060098154.

The spelling of 644090610 in words is "six hundred forty-four million, ninety thousand, six hundred ten".