18186121 has 2 divisors, whose sum is σ = 18186122. Its totient is φ = 18186120.

The previous prime is 18186089. The next prime is 18186127. The reversal of 18186121 is 12168181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17640000 + 546121 = 4200^2 + 739^2 .

It is an emirp because it is prime and its reverse (12168181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18186121 - 2⁵ = 18186089 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18186121.

It is not a weakly prime, because it can be changed into another prime (18186127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9093060 + 9093061.

It is an arithmetic number, because the mean of its divisors is an integer number (9093061).

Almost surely, 2^18186121 is an apocalyptic number.

It is an amenable number.

18186121 is a deficient number, since it is larger than the sum of its proper divisors (1).

18186121 is an equidigital number, since it uses as much as digits as its factorization.

18186121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 768, while the sum is 28.

The square root of 18186121 is about 4264.5188474200. The cubic root of 18186121 is about 262.9743308907.

The spelling of 18186121 in words is "eighteen million, one hundred eighty-six thousand, one hundred twenty-one".