18478081 has 2 divisors, whose sum is σ = 18478082. Its totient is φ = 18478080.

The previous prime is 18478073. The next prime is 18478093. The reversal of 18478081 is 18087481.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13571856 + 4906225 = 3684^2 + 2215^2 .

It is an emirp because it is prime and its reverse (18087481) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 18478081 - 2³ = 18478073 is a prime.

It is a super-2 number, since 2×18478081² = 682878954885122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 18478081.

It is not a weakly prime, because it can be changed into another prime (18478781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9239040 + 9239041.

It is an arithmetic number, because the mean of its divisors is an integer number (9239041).

Almost surely, 2^18478081 is an apocalyptic number.

It is an amenable number.

18478081 is a deficient number, since it is larger than the sum of its proper divisors (1).

18478081 is an equidigital number, since it uses as much as digits as its factorization.

18478081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14336, while the sum is 37.

The square root of 18478081 is about 4298.6138463463. The cubic root of 18478081 is about 264.3741299779.

The spelling of 18478081 in words is "eighteen million, four hundred seventy-eight thousand, eighty-one".