644002260 has 96 divisors (see below), whose sum is σ = 1986816384. Its totient is φ = 154560000.

The previous prime is 644002187. The next prime is 644002327. The reversal of 644002260 is 62200446.

It is a self number, because there is not a number n which added to its sum of digits gives 644002260.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 61830 + ... + 71490.

It is an arithmetic number, because the mean of its divisors is an integer number (20696004).

Almost surely, 2^644002260 is an apocalyptic number.

644002260 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 644002260, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (993408192).

644002260 is an abundant number, since it is smaller than the sum of its proper divisors (1342814124).

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

644002260 is a wasteful number, since it uses less digits than its factorization.

644002260 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9785 (or 9783 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 644002260 is about 25377.1996090979. The cubic root of 644002260 is about 863.5665210237.

The spelling of 644002260 in words is "six hundred forty-four million, two thousand, two hundred sixty".