18456121 has 2 divisors, whose sum is σ = 18456122. Its totient is φ = 18456120.

The previous prime is 18456107. The next prime is 18456157. The reversal of 18456121 is 12165481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16321600 + 2134521 = 4040^2 + 1461^2 .

It is a cyclic number.

It is not a de Polignac number, because 18456121 - 2⁹ = 18455609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18456121.

It is not a weakly prime, because it can be changed into another prime (18456161) 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, 9228060 + 9228061.

It is an arithmetic number, because the mean of its divisors is an integer number (9228061).

Almost surely, 2^18456121 is an apocalyptic number.

It is an amenable number.

18456121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18456121 is an equidigital number, since it uses as much as digits as its factorization.

18456121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1920, while the sum is 28.

The square root of 18456121 is about 4296.0587752032. The cubic root of 18456121 is about 264.2693579637.

The spelling of 18456121 in words is "eighteen million, four hundred fifty-six thousand, one hundred twenty-one".