18949771121 has 2 divisors, whose sum is σ = 18949771122. Its totient is φ = 18949771120.

The previous prime is 18949771117. The next prime is 18949771133. The reversal of 18949771121 is 12117794981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17961360400 + 988410721 = 134020^2 + 31439^2 .

It is a cyclic number.

It is not a de Polignac number, because 18949771121 - 2² = 18949771117 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18949771121.

It is not a weakly prime, because it can be changed into another prime (18949771111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9474885560 + 9474885561.

It is an arithmetic number, because the mean of its divisors is an integer number (9474885561).

Almost surely, 2^18949771121 is an apocalyptic number.

It is an amenable number.

18949771121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18949771121 is an equidigital number, since it uses as much as digits as its factorization.

18949771121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 50.

The spelling of 18949771121 in words is "eighteen billion, nine hundred forty-nine million, seven hundred seventy-one thousand, one hundred twenty-one".