18866081 has 4 divisors (see below), whose sum is σ = 20317332. Its totient is φ = 17414832.

The previous prime is 18866077. The next prime is 18866083. The reversal of 18866081 is 18066881.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11662225 + 7203856 = 3415^2 + 2684^2 .

It is a cyclic number.

It is not a de Polignac number, because 18866081 - 2² = 18866077 is a prime.

It is a super-2 number, since 2×18866081² = 711858024597122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18866083) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 725606 + ... + 725631.

It is an arithmetic number, because the mean of its divisors is an integer number (5079333).

Almost surely, 2^18866081 is an apocalyptic number.

It is an amenable number.

18866081 is a deficient number, since it is larger than the sum of its proper divisors (1451251).

18866081 is a wasteful number, since it uses less digits than its factorization.

18866081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1451250.

The product of its (nonzero) digits is 18432, while the sum is 38.

The square root of 18866081 is about 4343.5102164033. The cubic root of 18866081 is about 266.2117568706.

The spelling of 18866081 in words is "eighteen million, eight hundred sixty-six thousand, eighty-one".