18390431 has 2 divisors, whose sum is σ = 18390432. Its totient is φ = 18390430.

The previous prime is 18390403. The next prime is 18390433. The reversal of 18390431 is 13409381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18390431 - 2⁶ = 18390367 is a prime.

It is a super-2 number, since 2×18390431² = 676415904731522, which contains 22 as substring.

Together with 18390433, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18390394 and 18390403.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18390433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9195215 + 9195216.

It is an arithmetic number, because the mean of its divisors is an integer number (9195216).

Almost surely, 2^18390431 is an apocalyptic number.

18390431 is a deficient number, since it is larger than the sum of its proper divisors (1).

18390431 is an equidigital number, since it uses as much as digits as its factorization.

18390431 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 18390431 is about 4288.4065805378. The cubic root of 18390431 is about 263.9554514286.

The spelling of 18390431 in words is "eighteen million, three hundred ninety thousand, four hundred thirty-one".