18004861 has 4 divisors (see below), whose sum is σ = 20576992. Its totient is φ = 15432732.

The previous prime is 18004813. The next prime is 18004871. The reversal of 18004861 is 16840081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16840081 = 17 ⋅990593.

It is not a de Polignac number, because 18004861 - 2⁷ = 18004733 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 (18004801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1286055 + ... + 1286068.

It is an arithmetic number, because the mean of its divisors is an integer number (5144248).

Almost surely, 2^18004861 is an apocalyptic number.

It is an amenable number.

18004861 is a deficient number, since it is larger than the sum of its proper divisors (2572131).

18004861 is an equidigital number, since it uses as much as digits as its factorization.

18004861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2572130.

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 18004861 is about 4243.2135227914. The cubic root of 18004861 is about 262.0977288233.

The spelling of 18004861 in words is "eighteen million, four thousand, eight hundred sixty-one".