6639637643 has 2 divisors, whose sum is σ = 6639637644. Its totient is φ = 6639637642.

The previous prime is 6639637639. The next prime is 6639637649. The reversal of 6639637643 is 3467369366.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 6639637643 - 2² = 6639637639 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (6639637649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319818821 + 3319818822.

It is an arithmetic number, because the mean of its divisors is an integer number (3319818822).

Almost surely, 2^6639637643 is an apocalyptic number.

6639637643 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639637643 is an equidigital number, since it uses as much as digits as its factorization.

6639637643 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8817984, while the sum is 53.

The square root of 6639637643 is about 81483.9716938245. The cubic root of 6639637643 is about 1879.5250840343.

The spelling of 6639637643 in words is "six billion, six hundred thirty-nine million, six hundred thirty-seven thousand, six hundred forty-three".