640971582840 has 384 divisors, whose sum is σ = 2188901594880. Its totient is φ = 162483148800.

The previous prime is 640971582827. The next prime is 640971582871. The reversal of 640971582840 is 48285179046.

It is a happy number.

640971582840 is a `hidden beast` number, since 6 + 409 + 7 + 158 + 2 + 84 + 0 = 666.

640971582840 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 331936675 + ... + 331938605.

It is an arithmetic number, because the mean of its divisors is an integer number (5700264570).

Almost surely, 2^640971582840 is an apocalyptic number.

640971582840 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 640971582840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1094450797440).

640971582840 is an abundant number, since it is smaller than the sum of its proper divisors (1547930012040).

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

640971582840 is a wasteful number, since it uses less digits than its factorization.

640971582840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2555 (or 2548 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 640971582840 in words is "six hundred forty billion, nine hundred seventy-one million, five hundred eighty-two thousand, eight hundred forty".