18971971211 has 2 divisors, whose sum is σ = 18971971212. Its totient is φ = 18971971210.

The previous prime is 18971971189. The next prime is 18971971231. The reversal of 18971971211 is 11217917981.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18971971211 is a prime.

It is not a weakly prime, because it can be changed into another prime (18971971231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9485985605 + 9485985606.

It is an arithmetic number, because the mean of its divisors is an integer number (9485985606).

Almost surely, 2^18971971211 is an apocalyptic number.

18971971211 is a deficient number, since it is larger than the sum of its proper divisors (1).

18971971211 is an equidigital number, since it uses as much as digits as its factorization.

18971971211 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 63504, while the sum is 47.

The spelling of 18971971211 in words is "eighteen billion, nine hundred seventy-one million, nine hundred seventy-one thousand, two hundred eleven".