18006881 has 2 divisors, whose sum is σ = 18006882. Its totient is φ = 18006880.

The previous prime is 18006839. The next prime is 18006887. The reversal of 18006881 is 18860081.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15171025 + 2835856 = 3895^2 + 1684^2 .

It is an emirp because it is prime and its reverse (18860081) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18006881 is a prime.

It is a super-2 number, since 2×18006881² = 648495526696322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (18006887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9003440 + 9003441.

It is an arithmetic number, because the mean of its divisors is an integer number (9003441).

Almost surely, 2^18006881 is an apocalyptic number.

It is an amenable number.

18006881 is a deficient number, since it is larger than the sum of its proper divisors (1).

18006881 is an equidigital number, since it uses as much as digits as its factorization.

18006881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3072, while the sum is 32.

The square root of 18006881 is about 4243.4515432605. The cubic root of 18006881 is about 262.1075302063.

The spelling of 18006881 in words is "eighteen million, six thousand, eight hundred eighty-one".