6639856163 has 2 divisors, whose sum is σ = 6639856164. Its totient is φ = 6639856162.

The previous prime is 6639856121. The next prime is 6639856189. The reversal of 6639856163 is 3616589366.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6639856163 - 2²⁴ = 6623078947 is a prime.

It is not a weakly prime, because it can be changed into another prime (6639856193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3319928081 + 3319928082.

It is an arithmetic number, because the mean of its divisors is an integer number (3319928082).

Almost surely, 2^6639856163 is an apocalyptic number.

6639856163 is a deficient number, since it is larger than the sum of its proper divisors (1).

6639856163 is an equidigital number, since it uses as much as digits as its factorization.

6639856163 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4199040, while the sum is 53.

The square root of 6639856163 is about 81485.3125599945. The cubic root of 6639856163 is about 1879.5457030970.

The spelling of 6639856163 in words is "six billion, six hundred thirty-nine million, eight hundred fifty-six thousand, one hundred sixty-three".