18381731 has 2 divisors, whose sum is σ = 18381732. Its totient is φ = 18381730.

The previous prime is 18381691. The next prime is 18381733. The reversal of 18381731 is 13718381.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18381731 - 2¹⁰ = 18380707 is a prime.

It is a super-2 number, since 2×18381731² = 675776069112722, which contains 22 as substring.

Together with 18381733, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18381733) 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 as a sum of consecutive naturals, namely, 9190865 + 9190866.

It is an arithmetic number, because the mean of its divisors is an integer number (9190866).

Almost surely, 2^18381731 is an apocalyptic number.

18381731 is a deficient number, since it is larger than the sum of its proper divisors (1).

18381731 is an equidigital number, since it uses as much as digits as its factorization.

18381731 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 18381731 is about 4287.3920977676. The cubic root of 18381731 is about 263.9138215425.

The spelling of 18381731 in words is "eighteen million, three hundred eighty-one thousand, seven hundred thirty-one".