640963678464 has 216 divisors, whose sum is σ = 1975065936480. Its totient is φ = 199206027264.

The previous prime is 640963678423. The next prime is 640963678469. The reversal of 640963678464 is 464876369046.

640963678464 is a `hidden beast` number, since 6 + 40 + 9 + 63 + 6 + 78 + 464 = 666.

It is a super-3 number, since 3×640963678464³ (a number of 36 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (640963678469) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4114507 + ... + 4267445.

It is an arithmetic number, because the mean of its divisors is an integer number (9143823780).

Almost surely, 2^640963678464 is an apocalyptic number.

640963678464 is a gapful number since it is divisible by the number (64) 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 640963678464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (987532968240).

640963678464 is an abundant number, since it is smaller than the sum of its proper divisors (1334102258016).

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

640963678464 is a wasteful number, since it uses less digits than its factorization.

640963678464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153085 (or 153068 counting only the distinct ones).

The product of its (nonzero) digits is 125411328, while the sum is 63.

The spelling of 640963678464 in words is "six hundred forty billion, nine hundred sixty-three million, six hundred seventy-eight thousand, four hundred sixty-four".