18261431 has 2 divisors, whose sum is σ = 18261432. Its totient is φ = 18261430.

The previous prime is 18261409. The next prime is 18261433. The reversal of 18261431 is 13416281.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18261431 - 2⁶ = 18261367 is a prime.

It is a super-2 number, since 2×18261431² = 666959724335522, which contains 22 as substring.

Together with 18261433, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18261431.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18261433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9130715 + 9130716.

It is an arithmetic number, because the mean of its divisors is an integer number (9130716).

Almost surely, 2^18261431 is an apocalyptic number.

18261431 is a deficient number, since it is larger than the sum of its proper divisors (1).

18261431 is an equidigital number, since it uses as much as digits as its factorization.

18261431 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The square root of 18261431 is about 4273.3395605779. The cubic root of 18261431 is about 263.3368293435.

The spelling of 18261431 in words is "eighteen million, two hundred sixty-one thousand, four hundred thirty-one".