18243731 has 8 divisors (see below), whose sum is σ = 20100528. Its totient is φ = 16420000.

The previous prime is 18243721. The next prime is 18243733. The reversal of 18243731 is 13734281.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18243731 is a prime.

It is a super-2 number, since 2×18243731² = 665667441600722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 18243694 and 18243703.

It is not an unprimeable number, because it can be changed into a prime (18243733) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7100 + ... + 9321.

It is an arithmetic number, because the mean of its divisors is an integer number (2512566).

Almost surely, 2^18243731 is an apocalyptic number.

18243731 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18243731 is a deficient number, since it is larger than the sum of its proper divisors (1856797).

18243731 is a wasteful number, since it uses less digits than its factorization.

18243731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16533.

The product of its digits is 4032, while the sum is 29.

The square root of 18243731 is about 4271.2680786858. The cubic root of 18243731 is about 263.2517215807.

It can be divided in two parts, 1824 and 3731, that added together give a palindrome (5555).

The spelling of 18243731 in words is "eighteen million, two hundred forty-three thousand, seven hundred thirty-one".