18813161 has 2 divisors, whose sum is σ = 18813162. Its totient is φ = 18813160.

The previous prime is 18813133. The next prime is 18813163. The reversal of 18813161 is 16131881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15555136 + 3258025 = 3944^2 + 1805^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18813161 is a prime.

Together with 18813163, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18813163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9406580 + 9406581.

It is an arithmetic number, because the mean of its divisors is an integer number (9406581).

Almost surely, 2^18813161 is an apocalyptic number.

It is an amenable number.

18813161 is a deficient number, since it is larger than the sum of its proper divisors (1).

18813161 is an equidigital number, since it uses as much as digits as its factorization.

18813161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 29.

The square root of 18813161 is about 4337.4140913683. The cubic root of 18813161 is about 265.9626127565.

The spelling of 18813161 in words is "eighteen million, eight hundred thirteen thousand, one hundred sixty-one".