6643853639 has 2 divisors, whose sum is σ = 6643853640. Its totient is φ = 6643853638.

The previous prime is 6643853617. The next prime is 6643853641. The reversal of 6643853639 is 9363583466.

6643853639 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6643853639 - 2⁸ = 6643853383 is a prime.

Together with 6643853641, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6643853239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3321926819 + 3321926820.

It is an arithmetic number, because the mean of its divisors is an integer number (3321926820).

Almost surely, 2^6643853639 is an apocalyptic number.

6643853639 is a deficient number, since it is larger than the sum of its proper divisors (1).

6643853639 is an equidigital number, since it uses as much as digits as its factorization.

6643853639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8398080, while the sum is 53.

The square root of 6643853639 is about 81509.8376823313. The cubic root of 6643853639 is about 1879.9228162631.

The spelling of 6643853639 in words is "six billion, six hundred forty-three million, eight hundred fifty-three thousand, six hundred thirty-nine".