640815319768 has 128 divisors (see below), whose sum is σ = 1387181376000. Its totient is φ = 275264962560.

The previous prime is 640815319759. The next prime is 640815319769. The reversal of 640815319768 is 867913518046.

It is a Harshad number since it is a multiple of its sum of digits (58).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640815319769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 24015138 + ... + 24041806.

It is an arithmetic number, because the mean of its divisors is an integer number (10837354500).

Almost surely, 2^640815319768 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 640815319768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (693590688000).

640815319768 is an abundant number, since it is smaller than the sum of its proper divisors (746366056232).

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

640815319768 is a wasteful number, since it uses less digits than its factorization.

640815319768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27005 (or 27001 counting only the distinct ones).

The product of its (nonzero) digits is 8709120, while the sum is 58.

The spelling of 640815319768 in words is "six hundred forty billion, eight hundred fifteen million, three hundred nineteen thousand, seven hundred sixty-eight".