640108456765 has 8 divisors (see below), whose sum is σ = 768135763800. Its totient is φ = 512083021632.

The previous prime is 640108456753. The next prime is 640108456847. The reversal of 640108456765 is 567654801046.

It can be written as a sum of positive squares in 4 ways, for example, as 2630766681 + 637477690084 = 51291^2 + 798422^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 640108456765 - 2²⁵ = 640074902333 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 446947 + ... + 1216543.

It is an arithmetic number, because the mean of its divisors is an integer number (96016970475).

Almost surely, 2^640108456765 is an apocalyptic number.

It is an amenable number.

640108456765 is a deficient number, since it is larger than the sum of its proper divisors (128027307035).

640108456765 is a wasteful number, since it uses less digits than its factorization.

640108456765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 935951.

The product of its (nonzero) digits is 4838400, while the sum is 52.

The spelling of 640108456765 in words is "six hundred forty billion, one hundred eight million, four hundred fifty-six thousand, seven hundred sixty-five".