640663141 has 2 divisors, whose sum is σ = 640663142. Its totient is φ = 640663140.

The previous prime is 640663129. The next prime is 640663189. The reversal of 640663141 is 141366046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 633528900 + 7134241 = 25170^2 + 2671^2 .

It is a cyclic number.

It is not a de Polignac number, because 640663141 - 2¹¹ = 640661093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640666141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320331570 + 320331571.

It is an arithmetic number, because the mean of its divisors is an integer number (320331571).

Almost surely, 2^640663141 is an apocalyptic number.

It is an amenable number.

640663141 is a deficient number, since it is larger than the sum of its proper divisors (1).

640663141 is an equidigital number, since it uses as much as digits as its factorization.

640663141 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 31.

The square root of 640663141 is about 25311.3243628223. The cubic root of 640663141 is about 862.0714178477.

The spelling of 640663141 in words is "six hundred forty million, six hundred sixty-three thousand, one hundred forty-one".