18278089 has 4 divisors (see below), whose sum is σ = 18439956. Its totient is φ = 18116224.

The previous prime is 18278081. The next prime is 18278131. The reversal of 18278089 is 98087281.

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 1138489 + 17139600 = 1067^2 + 4140^2 .

It is a cyclic number.

It is not a de Polignac number, because 18278089 - 2³ = 18278081 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18278081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80764 + ... + 80989.

It is an arithmetic number, because the mean of its divisors is an integer number (4609989).

Almost surely, 2^18278089 is an apocalyptic number.

It is an amenable number.

18278089 is a deficient number, since it is larger than the sum of its proper divisors (161867).

18278089 is a wasteful number, since it uses less digits than its factorization.

18278089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161866.

The product of its (nonzero) digits is 64512, while the sum is 43.

The square root of 18278089 is about 4275.2881774215. The cubic root of 18278089 is about 263.4168765889.

The spelling of 18278089 in words is "eighteen million, two hundred seventy-eight thousand, eighty-nine".