640256136629 has 2 divisors, whose sum is σ = 640256136630. Its totient is φ = 640256136628.

The previous prime is 640256136607. The next prime is 640256136697. The reversal of 640256136629 is 926631652046.

640256136629 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., 640036800529 + 219336100 = 800023^2 + 14810^2 .

It is a cyclic number.

It is not a de Polignac number, because 640256136629 - 2¹² = 640256132533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640256136829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320128068314 + 320128068315.

It is an arithmetic number, because the mean of its divisors is an integer number (320128068315).

Almost surely, 2^640256136629 is an apocalyptic number.

It is an amenable number.

640256136629 is a deficient number, since it is larger than the sum of its proper divisors (1).

640256136629 is an equidigital number, since it uses as much as digits as its factorization.

640256136629 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2799360, while the sum is 50.

The spelling of 640256136629 in words is "six hundred forty billion, two hundred fifty-six million, one hundred thirty-six thousand, six hundred twenty-nine".