18004081 has 2 divisors, whose sum is σ = 18004082. Its totient is φ = 18004080.

The previous prime is 18004067. The next prime is 18004121. The reversal of 18004081 is 18040081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13838400 + 4165681 = 3720^2 + 2041^2 .

It is an emirp because it is prime and its reverse (18040081) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18004081 - 2¹⁵ = 17971313 is a prime.

It is a super-2 number, since 2×18004081² = 648293865309122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (18004061) 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, 9002040 + 9002041.

It is an arithmetic number, because the mean of its divisors is an integer number (9002041).

Almost surely, 2^18004081 is an apocalyptic number.

It is an amenable number.

18004081 is a deficient number, since it is larger than the sum of its proper divisors (1).

18004081 is an equidigital number, since it uses as much as digits as its factorization.

18004081 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 18004081 is about 4243.1216103242. The cubic root of 18004081 is about 262.0939439347.

The spelling of 18004081 in words is "eighteen million, four thousand, eighty-one".