640833792761 has 8 divisors (see below), whose sum is σ = 673987094784. Its totient is φ = 608460568560.

The previous prime is 640833792751. The next prime is 640833792839. The reversal of 640833792761 is 167297338046.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640833792761 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640833792697 and 640833792706.

It is not an unprimeable number, because it can be changed into a prime (640833792751) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195017771 + ... + 195021056.

It is an arithmetic number, because the mean of its divisors is an integer number (84248386848).

Almost surely, 2^640833792761 is an apocalyptic number.

It is an amenable number.

640833792761 is a deficient number, since it is larger than the sum of its proper divisors (33153302023).

640833792761 is a wasteful number, since it uses less digits than its factorization.

640833792761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390038911.

The product of its (nonzero) digits is 9144576, while the sum is 56.

The spelling of 640833792761 in words is "six hundred forty billion, eight hundred thirty-three million, seven hundred ninety-two thousand, seven hundred sixty-one".