644680500 has 96 divisors (see below), whose sum is σ = 1895013120. Its totient is φ = 170294400.

The previous prime is 644680483. The next prime is 644680541. The reversal of 644680500 is 5086446.

It is a happy number.

It is a super-2 number, since 2×644680500² = 831225894160500000, which contains 22 as substring.

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, 161529 + ... + 165471.

It is an arithmetic number, because the mean of its divisors is an integer number (19739720).

Almost surely, 2^644680500 is an apocalyptic number.

644680500 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 644680500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (947506560).

644680500 is an abundant number, since it is smaller than the sum of its proper divisors (1250332620).

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

644680500 is a wasteful number, since it uses less digits than its factorization.

644680500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4074 (or 4062 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

The square root of 644680500 is about 25390.5592691457. The cubic root of 644680500 is about 863.8695737194.

The spelling of 644680500 in words is "six hundred forty-four million, six hundred eighty thousand, five hundred".