18631121 has 2 divisors, whose sum is σ = 18631122. Its totient is φ = 18631120.

The previous prime is 18631111. The next prime is 18631139. The reversal of 18631121 is 12113681.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18190225 + 440896 = 4265^2 + 664^2 .

It is a cyclic number.

It is not a de Polignac number, because 18631121 - 2⁶ = 18631057 is a prime.

It is not a weakly prime, because it can be changed into another prime (18631111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9315560 + 9315561.

It is an arithmetic number, because the mean of its divisors is an integer number (9315561).

Almost surely, 2^18631121 is an apocalyptic number.

It is an amenable number.

18631121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18631121 is an equidigital number, since it uses as much as digits as its factorization.

18631121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 288, while the sum is 23.

The square root of 18631121 is about 4316.3782271715. The cubic root of 18631121 is about 265.1019946772.

The spelling of 18631121 in words is "eighteen million, six hundred thirty-one thousand, one hundred twenty-one".