18688231 has 4 divisors (see below), whose sum is σ = 18768672. Its totient is φ = 18607792.

The previous prime is 18688211. The next prime is 18688249. The reversal of 18688231 is 13288681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13288681 = 7 ⋅1898383.

It is a cyclic number.

It is not a de Polignac number, because 18688231 - 2²³ = 10299623 is a prime.

It is a super-2 number, since 2×18688231² = 698499955818722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18688211) 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 in 3 ways as a sum of consecutive naturals, for example, 39871 + ... + 40336.

It is an arithmetic number, because the mean of its divisors is an integer number (4692168).

Almost surely, 2^18688231 is an apocalyptic number.

18688231 is a deficient number, since it is larger than the sum of its proper divisors (80441).

18688231 is an equidigital number, since it uses as much as digits as its factorization.

18688231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80440.

The product of its digits is 18432, while the sum is 37.

The square root of 18688231 is about 4322.9886652639. The cubic root of 18688231 is about 265.3725908780.

The spelling of 18688231 in words is "eighteen million, six hundred eighty-eight thousand, two hundred thirty-one".