640640159989 has 2 divisors, whose sum is σ = 640640159990. Its totient is φ = 640640159988.

The previous prime is 640640159963. The next prime is 640640160007. The reversal of 640640159989 is 989951046046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 324947881764 + 315692278225 = 570042^2 + 561865^2 .

It is a cyclic number.

It is not a de Polignac number, because 640640159989 - 2²⁵ = 640606605557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640640159959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320320079994 + 320320079995.

It is an arithmetic number, because the mean of its divisors is an integer number (320320079995).

Almost surely, 2^640640159989 is an apocalyptic number.

It is an amenable number.

640640159989 is a deficient number, since it is larger than the sum of its proper divisors (1).

640640159989 is an equidigital number, since it uses as much as digits as its factorization.

640640159989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16796160, while the sum is 61.

The spelling of 640640159989 in words is "six hundred forty billion, six hundred forty million, one hundred fifty-nine thousand, nine hundred eighty-nine".