6665521663 has 2 divisors, whose sum is σ = 6665521664. Its totient is φ = 6665521662.

The previous prime is 6665521609. The next prime is 6665521711. The reversal of 6665521663 is 3661255666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6665521663 - 2⁹ = 6665521151 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6665521363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3332760831 + 3332760832.

It is an arithmetic number, because the mean of its divisors is an integer number (3332760832).

Almost surely, 2^6665521663 is an apocalyptic number.

6665521663 is a deficient number, since it is larger than the sum of its proper divisors (1).

6665521663 is an equidigital number, since it uses as much as digits as its factorization.

6665521663 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1166400, while the sum is 46.

The square root of 6665521663 is about 81642.6461048391. The cubic root of 6665521663 is about 1881.9643026225.

The spelling of 6665521663 in words is "six billion, six hundred sixty-five million, five hundred twenty-one thousand, six hundred sixty-three".