6645917879 has 2 divisors, whose sum is σ = 6645917880. Its totient is φ = 6645917878.

The previous prime is 6645917783. The next prime is 6645917891. The reversal of 6645917879 is 9787195466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6645917879 - 2²⁴ = 6629140663 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 (6645911879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3322958939 + 3322958940.

It is an arithmetic number, because the mean of its divisors is an integer number (3322958940).

Almost surely, 2^6645917879 is an apocalyptic number.

6645917879 is a deficient number, since it is larger than the sum of its proper divisors (1).

6645917879 is an equidigital number, since it uses as much as digits as its factorization.

6645917879 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22861440, while the sum is 62.

The square root of 6645917879 is about 81522.4992195406. The cubic root of 6645917879 is about 1880.1174929399.

The spelling of 6645917879 in words is "six billion, six hundred forty-five million, nine hundred seventeen thousand, eight hundred seventy-nine".