640430963527679 has 4 divisors (see below), whose sum is σ = 655324706865576. Its totient is φ = 625537220189784.

The previous prime is 640430963527627. The next prime is 640430963527717. The reversal of 640430963527679 is 976725369034046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640430963527679 - 2⁸ = 640430963527423 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640430963523679) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7446871668884 + ... + 7446871668969.

It is an arithmetic number, because the mean of its divisors is an integer number (163831176716394).

Almost surely, 2^{640430963527679} is an apocalyptic number.

640430963527679 is a deficient number, since it is larger than the sum of its proper divisors (14893743337897).

640430963527679 is a wasteful number, since it uses less digits than its factorization.

640430963527679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14893743337896.

The product of its (nonzero) digits is 1234517760, while the sum is 71.

The spelling of 640430963527679 in words is "six hundred forty trillion, four hundred thirty billion, nine hundred sixty-three million, five hundred twenty-seven thousand, six hundred seventy-nine".