640344960 has 128 divisors (see below), whose sum is σ = 2267949600. Its totient is φ = 170754048.

The previous prime is 640344937. The next prime is 640344979. The reversal of 640344960 is 69443046.

640344960 is a `hidden beast` number, since 640 + 3 + 4 + 4 + 9 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (128).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1249 + ... + 35808.

Almost surely, 2^640344960 is an apocalyptic number.

640344960 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 640344960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1133974800).

640344960 is an abundant number, since it is smaller than the sum of its proper divisors (1627604640).

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

640344960 is a wasteful number, since it uses less digits than its factorization.

640344960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37085 (or 37067 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 640344960 is about 25305.0382335218. The cubic root of 640344960 is about 861.9286802426.

The spelling of 640344960 in words is "six hundred forty million, three hundred forty-four thousand, nine hundred sixty".