18181969873 has 2 divisors, whose sum is σ = 18181969874. Its totient is φ = 18181969872.

The previous prime is 18181969849. The next prime is 18181969889. The reversal of 18181969873 is 37896918181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9931517649 + 8250452224 = 99657^2 + 90832^2 .

It is a cyclic number.

It is not a de Polignac number, because 18181969873 - 2²¹ = 18179872721 is a prime.

It is a super-2 number, since 2×18181969873² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18181969823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9090984936 + 9090984937.

It is an arithmetic number, because the mean of its divisors is an integer number (9090984937).

Almost surely, 2^18181969873 is an apocalyptic number.

It is an amenable number.

18181969873 is a deficient number, since it is larger than the sum of its proper divisors (1).

18181969873 is an equidigital number, since it uses as much as digits as its factorization.

18181969873 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5225472, while the sum is 61.

The spelling of 18181969873 in words is "eighteen billion, one hundred eighty-one million, nine hundred sixty-nine thousand, eight hundred seventy-three".