640779285240 has 128 divisors (see below), whose sum is σ = 2140179148800. Its totient is φ = 170534620800.

The previous prime is 640779285239. The next prime is 640779285277. The reversal of 640779285240 is 42582977046.

640779285240 is a `hidden beast` number, since 6 + 40 + 7 + 79 + 2 + 8 + 524 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 46536 + ... + 1133015.

It is an arithmetic number, because the mean of its divisors is an integer number (16720149600).

Almost surely, 2^640779285240 is an apocalyptic number.

640779285240 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 640779285240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1070089574400).

640779285240 is an abundant number, since it is smaller than the sum of its proper divisors (1499399863560).

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

640779285240 is a wasteful number, since it uses less digits than its factorization.

640779285240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1180074 (or 1180064 counting only the distinct ones).

The product of its (nonzero) digits is 6773760, while the sum is 54.

The spelling of 640779285240 in words is "six hundred forty billion, seven hundred seventy-nine million, two hundred eighty-five thousand, two hundred forty".