18208231 has 2 divisors, whose sum is σ = 18208232. Its totient is φ = 18208230.

The previous prime is 18208189. The next prime is 18208261. The reversal of 18208231 is 13280281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18208231 - 2⁷ = 18208103 is a prime.

It is a super-2 number, since 2×18208231² = 663079352298722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 18208196 and 18208205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18208261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9104115 + 9104116.

It is an arithmetic number, because the mean of its divisors is an integer number (9104116).

Almost surely, 2^18208231 is an apocalyptic number.

18208231 is a deficient number, since it is larger than the sum of its proper divisors (1).

18208231 is an equidigital number, since it uses as much as digits as its factorization.

18208231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 768, while the sum is 25.

The square root of 18208231 is about 4267.1103805737. The cubic root of 18208231 is about 263.0808591557.

The spelling of 18208231 in words is "eighteen million, two hundred eight thousand, two hundred thirty-one".