18002161 has 2 divisors, whose sum is σ = 18002162. Its totient is φ = 18002160.

The previous prime is 18002141. The next prime is 18002189. The reversal of 18002161 is 16120081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17430625 + 571536 = 4175^2 + 756^2 .

It is a cyclic number.

It is not a de Polignac number, because 18002161 - 2⁵ = 18002129 is a prime.

It is not a weakly prime, because it can be changed into another prime (18002111) 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, 9001080 + 9001081.

It is an arithmetic number, because the mean of its divisors is an integer number (9001081).

Almost surely, 2^18002161 is an apocalyptic number.

It is an amenable number.

18002161 is a deficient number, since it is larger than the sum of its proper divisors (1).

18002161 is an equidigital number, since it uses as much as digits as its factorization.

18002161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 18002161 is about 4242.8953557683. The cubic root of 18002161 is about 262.0846268200.

The spelling of 18002161 in words is "eighteen million, two thousand, one hundred sixty-one".