640991159 has 2 divisors, whose sum is σ = 640991160. Its totient is φ = 640991158.

The previous prime is 640991149. The next prime is 640991161. The reversal of 640991159 is 951199046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640991159 - 2²⁴ = 624213943 is a prime.

Together with 640991161, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640991129) 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, 320495579 + 320495580.

It is an arithmetic number, because the mean of its divisors is an integer number (320495580).

Almost surely, 2^640991159 is an apocalyptic number.

640991159 is a deficient number, since it is larger than the sum of its proper divisors (1).

640991159 is an equidigital number, since it uses as much as digits as its factorization.

640991159 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 87480, while the sum is 44.

The square root of 640991159 is about 25317.8032024897. The cubic root of 640991159 is about 862.2185189153.

The spelling of 640991159 in words is "six hundred forty million, nine hundred ninety-one thousand, one hundred fifty-nine".