18112121 has 2 divisors, whose sum is σ = 18112122. Its totient is φ = 18112120.

The previous prime is 18112019. The next prime is 18112141. The reversal of 18112121 is 12121181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13424896 + 4687225 = 3664^2 + 2165^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18112121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18112121.

It is not a weakly prime, because it can be changed into another prime (18112141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9056060 + 9056061.

It is an arithmetic number, because the mean of its divisors is an integer number (9056061).

Almost surely, 2^18112121 is an apocalyptic number.

It is an amenable number.

18112121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18112121 is an equidigital number, since it uses as much as digits as its factorization.

18112121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32, while the sum is 17.

The square root of 18112121 is about 4255.8337608511. The cubic root of 18112121 is about 262.6171619093.

The spelling of 18112121 in words is "eighteen million, one hundred twelve thousand, one hundred twenty-one".