640749312 has 576 divisors, whose sum is σ = 2472422400. Its totient is φ = 159252480.

The previous prime is 640749299. The next prime is 640749349. The reversal of 640749312 is 213947046.

640749312 is a `hidden beast` number, since 640 + 7 + 4 + 9 + 3 + 1 + 2 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

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 63 ways as a sum of consecutive naturals, for example, 15628012 + ... + 15628052.

It is an arithmetic number, because the mean of its divisors is an integer number (4292400).

Almost surely, 2^640749312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640749312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1236211200).

640749312 is an abundant number, since it is smaller than the sum of its proper divisors (1831673088).

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

640749312 is a wasteful number, since it uses less digits than its factorization.

640749312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 640749312 is about 25313.0265278572. The cubic root of 640749312 is about 862.1100664610.

The spelling of 640749312 in words is "six hundred forty million, seven hundred forty-nine thousand, three hundred twelve".