18509431 has 2 divisors, whose sum is σ = 18509432. Its totient is φ = 18509430.

The previous prime is 18509389. The next prime is 18509441. The reversal of 18509431 is 13490581.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18509431 - 2¹¹ = 18507383 is a prime.

It is a super-2 number, since 2×18509431² = 685198071887522, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18509393 and 18509402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18509441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9254715 + 9254716.

It is an arithmetic number, because the mean of its divisors is an integer number (9254716).

Almost surely, 2^18509431 is an apocalyptic number.

18509431 is a deficient number, since it is larger than the sum of its proper divisors (1).

18509431 is an equidigital number, since it uses as much as digits as its factorization.

18509431 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 31.

The square root of 18509431 is about 4302.2588253149. The cubic root of 18509431 is about 264.5235583044.

The spelling of 18509431 in words is "eighteen million, five hundred nine thousand, four hundred thirty-one".