640431360 has 432 divisors, whose sum is σ = 2410611840. Its totient is φ = 162570240.

The previous prime is 640431329. The next prime is 640431377. The reversal of 640431360 is 63134046.

640431360 is a `hidden beast` number, since 640 + 4 + 3 + 13 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9020125 + ... + 9020195.

It is an arithmetic number, because the mean of its divisors is an integer number (5580120).

Almost surely, 2^640431360 is an apocalyptic number.

640431360 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 640431360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1205305920).

640431360 is an abundant number, since it is smaller than the sum of its proper divisors (1770180480).

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

640431360 is an equidigital number, since it uses as much as digits as its factorization.

640431360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 136 (or 110 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 640431360 is about 25306.7453458559. The cubic root of 640431360 is about 861.9674443950.

The spelling of 640431360 in words is "six hundred forty million, four hundred thirty-one thousand, three hundred sixty".