18868081 has 2 divisors, whose sum is σ = 18868082. Its totient is φ = 18868080.

The previous prime is 18868063. The next prime is 18868097. The reversal of 18868081 is 18086881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10112400 + 8755681 = 3180^2 + 2959^2 .

It is an emirp because it is prime and its reverse (18086881) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18868081 - 2⁵ = 18868049 is a prime.

It is a super-2 number, since 2×18868081² = 712008961245122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18868001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9434040 + 9434041.

It is an arithmetic number, because the mean of its divisors is an integer number (9434041).

Almost surely, 2^18868081 is an apocalyptic number.

It is an amenable number.

18868081 is a deficient number, since it is larger than the sum of its proper divisors (1).

18868081 is an equidigital number, since it uses as much as digits as its factorization.

18868081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24576, while the sum is 40.

The square root of 18868081 is about 4343.7404388384. The cubic root of 18868081 is about 266.2211636061.

The spelling of 18868081 in words is "eighteen million, eight hundred sixty-eight thousand, eighty-one".