18201121 has 2 divisors, whose sum is σ = 18201122. Its totient is φ = 18201120.

The previous prime is 18201103. The next prime is 18201181. The reversal of 18201121 is 12110281.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12702096 + 5499025 = 3564^2 + 2345^2 .

It is a cyclic number.

It is not a de Polignac number, because 18201121 - 2¹¹ = 18199073 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 18201095 and 18201104.

It is not a weakly prime, because it can be changed into another prime (18201181) 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, 9100560 + 9100561.

It is an arithmetic number, because the mean of its divisors is an integer number (9100561).

Almost surely, 2^18201121 is an apocalyptic number.

It is an amenable number.

18201121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18201121 is an equidigital number, since it uses as much as digits as its factorization.

18201121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 18201121 is about 4266.2771827438. The cubic root of 18201121 is about 263.0466118524.

The spelling of 18201121 in words is "eighteen million, two hundred one thousand, one hundred twenty-one".