18971971189 has 2 divisors, whose sum is σ = 18971971190. Its totient is φ = 18971971188.

The previous prime is 18971971163. The next prime is 18971971211. The reversal of 18971971189 is 98117917981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17102100625 + 1869870564 = 130775^2 + 43242^2 .

It is a cyclic number.

It is not a de Polignac number, because 18971971189 - 2⁵ = 18971971157 is a prime.

It is a super-5 number, since 5×18971971189⁵ (a number of 53 digits) contains 55555 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18971971159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9485985594 + 9485985595.

It is an arithmetic number, because the mean of its divisors is an integer number (9485985595).

Almost surely, 2^18971971189 is an apocalyptic number.

It is an amenable number.

18971971189 is a deficient number, since it is larger than the sum of its proper divisors (1).

18971971189 is an equidigital number, since it uses as much as digits as its factorization.

18971971189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 61.

The spelling of 18971971189 in words is "eighteen billion, nine hundred seventy-one million, nine hundred seventy-one thousand, one hundred eighty-nine".