18123861 has 12 divisors (see below), whose sum is σ = 27647072. Its totient is φ = 10345344.

The previous prime is 18123857. The next prime is 18123877. The reversal of 18123861 is 16832181.

It is not a de Polignac number, because 18123861 - 2² = 18123857 is a prime.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

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 polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19045 + ... + 19973.

Almost surely, 2^18123861 is an apocalyptic number.

It is an amenable number.

18123861 is a deficient number, since it is larger than the sum of its proper divisors (9523211).

18123861 is an frugal number, since it uses more digits than its factorization.

18123861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1868 (or 939 counting only the distinct ones).

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

The square root of 18123861 is about 4257.2128206140. The cubic root of 18123861 is about 262.6738911309.

It can be divided in two parts, 181 and 23861, that added together give a palindrome (24042).

The spelling of 18123861 in words is "eighteen million, one hundred twenty-three thousand, eight hundred sixty-one".