644610960 has 280 divisors, whose sum is σ = 2569686720. Its totient is φ = 147246336.

The previous prime is 644610943. The next prime is 644610983. The reversal of 644610960 is 69016446.

644610960 is a `hidden beast` number, since 644 + 6 + 1 + 0 + 9 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (280).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 407451 + ... + 409029.

Almost surely, 2^644610960 is an apocalyptic number.

644610960 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 644610960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1284843360).

644610960 is an abundant number, since it is smaller than the sum of its proper divisors (1925075760).

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

644610960 is a wasteful number, since it uses less digits than its factorization.

644610960 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1617 (or 1596 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The square root of 644610960 is about 25389.1898255931. The cubic root of 644610960 is about 863.8385114851.

The spelling of 644610960 in words is "six hundred forty-four million, six hundred ten thousand, nine hundred sixty".