640436646659 has 2 divisors, whose sum is σ = 640436646660. Its totient is φ = 640436646658.

The previous prime is 640436646581. The next prime is 640436646667. The reversal of 640436646659 is 956646634046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640436646659 - 2⁸ = 640436646403 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 640436646598 and 640436646607.

It is not a weakly prime, because it can be changed into another prime (640436636659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320218323329 + 320218323330.

It is an arithmetic number, because the mean of its divisors is an integer number (320218323330).

Almost surely, 2^640436646659 is an apocalyptic number.

640436646659 is a deficient number, since it is larger than the sum of its proper divisors (1).

640436646659 is an equidigital number, since it uses as much as digits as its factorization.

640436646659 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 67184640, while the sum is 59.

The spelling of 640436646659 in words is "six hundred forty billion, four hundred thirty-six million, six hundred forty-six thousand, six hundred fifty-nine".