20661136163 has 4 divisors (see below), whose sum is σ = 20661714168. Its totient is φ = 20660558160.

The previous prime is 20661136157. The next prime is 20661136229. The reversal of 20661136163 is 36163116602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20661136163 - 2¹⁶ = 20661070627 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20661136763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 231581 + ... + 308142.

It is an arithmetic number, because the mean of its divisors is an integer number (5165428542).

Almost surely, 2^20661136163 is an apocalyptic number.

20661136163 is a deficient number, since it is larger than the sum of its proper divisors (578005).

20661136163 is an equidigital number, since it uses as much as digits as its factorization.

20661136163 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578004.

The product of its (nonzero) digits is 23328, while the sum is 35.

The spelling of 20661136163 in words is "twenty billion, six hundred sixty-one million, one hundred thirty-six thousand, one hundred sixty-three".