640546818912 has 768 divisors, whose sum is σ = 2533616547840. Its totient is φ = 152036352000.

The previous prime is 640546818803. The next prime is 640546818913. The reversal of 640546818912 is 219818645046.

640546818912 is a `hidden beast` number, since 6 + 4 + 0 + 546 + 8 + 1 + 8 + 91 + 2 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640546818913) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 87347598 + ... + 87354930.

It is an arithmetic number, because the mean of its divisors is an integer number (3298979880).

Almost surely, 2^640546818912 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 640546818912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1266808273920).

640546818912 is an abundant number, since it is smaller than the sum of its proper divisors (1893069728928).

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

640546818912 is a wasteful number, since it uses less digits than its factorization.

640546818912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7484 (or 7470 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 54.

The spelling of 640546818912 in words is "six hundred forty billion, five hundred forty-six million, eight hundred eighteen thousand, nine hundred twelve".