640889713 has 2 divisors, whose sum is σ = 640889714. Its totient is φ = 640889712.

The previous prime is 640889707. The next prime is 640889747. The reversal of 640889713 is 317988046.

It is a happy number.

640889713 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 571783744 + 69105969 = 23912^2 + 8313^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640889713 is a prime.

It is not a weakly prime, because it can be changed into another prime (640889113) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320444856 + 320444857.

It is an arithmetic number, because the mean of its divisors is an integer number (320444857).

Almost surely, 2^640889713 is an apocalyptic number.

It is an amenable number.

640889713 is a deficient number, since it is larger than the sum of its proper divisors (1).

640889713 is an equidigital number, since it uses as much as digits as its factorization.

640889713 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 46.

The square root of 640889713 is about 25315.7996713515. The cubic root of 640889713 is about 862.1730303864.

The spelling of 640889713 in words is "six hundred forty million, eight hundred eighty-nine thousand, seven hundred thirteen".