641635919 has 2 divisors, whose sum is σ = 641635920. Its totient is φ = 641635918.

The previous prime is 641635901. The next prime is 641635979. The reversal of 641635919 is 919536146.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 641635919 - 2⁸ = 641635663 is a prime.

It is a super-2 number, since 2×641635919² = 823393305101949122, which contains 22 as substring.

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 641635919.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (641635979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320817959 + 320817960.

It is an arithmetic number, because the mean of its divisors is an integer number (320817960).

Almost surely, 2^641635919 is an apocalyptic number.

641635919 is a deficient number, since it is larger than the sum of its proper divisors (1).

641635919 is an equidigital number, since it uses as much as digits as its factorization.

641635919 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 174960, while the sum is 44.

The square root of 641635919 is about 25330.5333342984. The cubic root of 641635919 is about 862.5075180749.

The spelling of 641635919 in words is "six hundred forty-one million, six hundred thirty-five thousand, nine hundred nineteen".