640109306957 has 2 divisors, whose sum is σ = 640109306958. Its totient is φ = 640109306956.

The previous prime is 640109306891. The next prime is 640109306971. The reversal of 640109306957 is 759603901046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 613372478761 + 26736828196 = 783181^2 + 163514^2 .

It is a cyclic number.

It is not a de Polignac number, because 640109306957 - 2⁸ = 640109306701 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640109306357) 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 as a sum of consecutive naturals, namely, 320054653478 + 320054653479.

It is an arithmetic number, because the mean of its divisors is an integer number (320054653479).

Almost surely, 2^640109306957 is an apocalyptic number.

It is an amenable number.

640109306957 is a deficient number, since it is larger than the sum of its proper divisors (1).

640109306957 is an equidigital number, since it uses as much as digits as its factorization.

640109306957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1224720, while the sum is 50.

The spelling of 640109306957 in words is "six hundred forty billion, one hundred nine million, three hundred six thousand, nine hundred fifty-seven".