18681231 has 8 divisors (see below), whose sum is σ = 25438464. Its totient is φ = 12189080.

The previous prime is 18681227. The next prime is 18681239. The reversal of 18681231 is 13218681.

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

It is a cyclic number.

It is not a de Polignac number, because 18681231 - 2² = 18681227 is a prime.

It is a super-2 number, since 2×18681231² = 697976783350722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18681239) 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 7 ways as a sum of consecutive naturals, for example, 66105 + ... + 66386.

It is an arithmetic number, because the mean of its divisors is an integer number (3179808).

Almost surely, 2^18681231 is an apocalyptic number.

18681231 is a deficient number, since it is larger than the sum of its proper divisors (6757233).

18681231 is a wasteful number, since it uses less digits than its factorization.

18681231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 132541.

The product of its digits is 2304, while the sum is 30.

The square root of 18681231 is about 4322.1789643651. The cubic root of 18681231 is about 265.3394534431.

The spelling of 18681231 in words is "eighteen million, six hundred eighty-one thousand, two hundred thirty-one".