18123831 has 20 divisors (see below), whose sum is σ = 29536584. Its totient is φ = 10983600.

The previous prime is 18123829. The next prime is 18123857. The reversal of 18123831 is 13832181.

It is not a de Polignac number, because 18123831 - 2¹ = 18123829 is a prime.

It is a super-2 number, since 2×18123831² = 656946500233122, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 18123795 and 18123804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18123881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 9280 + ... + 11061.

Almost surely, 2^18123831 is an apocalyptic number.

18123831 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18123831 is a deficient number, since it is larger than the sum of its proper divisors (11412753).

18123831 is a wasteful number, since it uses less digits than its factorization.

18123831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20364 (or 20355 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 18123831 is about 4257.2092971805. The cubic root of 18123831 is about 262.6737461982.

The spelling of 18123831 in words is "eighteen million, one hundred twenty-three thousand, eight hundred thirty-one".