640253460991 has 2 divisors, whose sum is σ = 640253460992. Its totient is φ = 640253460990.

The previous prime is 640253460943. The next prime is 640253461007. The reversal of 640253460991 is 199064352046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640253460991 - 2⁹ = 640253460479 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640253460391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320126730495 + 320126730496.

It is an arithmetic number, because the mean of its divisors is an integer number (320126730496).

Almost surely, 2^640253460991 is an apocalyptic number.

640253460991 is a deficient number, since it is larger than the sum of its proper divisors (1).

640253460991 is an equidigital number, since it uses as much as digits as its factorization.

640253460991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1399680, while the sum is 49.

The spelling of 640253460991 in words is "six hundred forty billion, two hundred fifty-three million, four hundred sixty thousand, nine hundred ninety-one".