640700959 has 4 divisors (see below), whose sum is σ = 640800504. Its totient is φ = 640601416.

The previous prime is 640700911. The next prime is 640701037. The reversal of 640700959 is 959007046.

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 640700959 - 2¹⁷ = 640569887 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 (640700059) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39397 + ... + 53230.

It is an arithmetic number, because the mean of its divisors is an integer number (160200126).

Almost surely, 2^640700959 is an apocalyptic number.

640700959 is a deficient number, since it is larger than the sum of its proper divisors (99545).

640700959 is an equidigital number, since it uses as much as digits as its factorization.

640700959 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99544.

The product of its (nonzero) digits is 68040, while the sum is 40.

The square root of 640700959 is about 25312.0714087172. The cubic root of 640700959 is about 862.0883800511.

The spelling of 640700959 in words is "six hundred forty million, seven hundred thousand, nine hundred fifty-nine".