640621218311 has 2 divisors, whose sum is σ = 640621218312. Its totient is φ = 640621218310.

The previous prime is 640621218287. The next prime is 640621218317. The reversal of 640621218311 is 113812126046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640621218311 - 2²² = 640617024007 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640621218317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320310609155 + 320310609156.

It is an arithmetic number, because the mean of its divisors is an integer number (320310609156).

Almost surely, 2^640621218311 is an apocalyptic number.

640621218311 is a deficient number, since it is larger than the sum of its proper divisors (1).

640621218311 is an equidigital number, since it uses as much as digits as its factorization.

640621218311 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 35.

The spelling of 640621218311 in words is "six hundred forty billion, six hundred twenty-one million, two hundred eighteen thousand, three hundred eleven".