641887999979 has 2 divisors, whose sum is σ = 641887999980. Its totient is φ = 641887999978.

The previous prime is 641887999933. The next prime is 641887999981. The reversal of 641887999979 is 979999788146.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-641887999979 is a prime.

Together with 641887999981, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 641887999979.

It is not a weakly prime, because it can be changed into another prime (641887990979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320943999989 + 320943999990.

It is an arithmetic number, because the mean of its divisors is an integer number (320943999990).

Almost surely, 2^641887999979 is an apocalyptic number.

641887999979 is a deficient number, since it is larger than the sum of its proper divisors (1).

641887999979 is an equidigital number, since it uses as much as digits as its factorization.

641887999979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4444263936, while the sum is 86.

The spelling of 641887999979 in words is "six hundred forty-one billion, eight hundred eighty-seven million, nine hundred ninety-nine thousand, nine hundred seventy-nine".