18143861 has 4 divisors (see below), whose sum is σ = 18486252. Its totient is φ = 17801472.

The previous prime is 18143791. The next prime is 18143863. The reversal of 18143861 is 16834181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 7187761 + 10956100 = 2681^2 + 3310^2 .

It is a cyclic number.

It is not a de Polignac number, because 18143861 - 2²² = 13949557 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18143863) 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, 171116 + ... + 171221.

It is an arithmetic number, because the mean of its divisors is an integer number (4621563).

Almost surely, 2^18143861 is an apocalyptic number.

It is an amenable number.

18143861 is a deficient number, since it is larger than the sum of its proper divisors (342391).

18143861 is an equidigital number, since it uses as much as digits as its factorization.

18143861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342390.

The product of its digits is 4608, while the sum is 32.

The square root of 18143861 is about 4259.5611276281. The cubic root of 18143861 is about 262.7704773674.

The spelling of 18143861 in words is "eighteen million, one hundred forty-three thousand, eight hundred sixty-one".