18187421 has 8 divisors (see below), whose sum is σ = 21456384. Its totient is φ = 15086160.

The previous prime is 18187381. The next prime is 18187441. The reversal of 18187421 is 12478181.

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 18187421 - 2⁶ = 18187357 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 (18187441) 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 7 ways as a sum of consecutive naturals, for example, 41690 + ... + 42123.

It is an arithmetic number, because the mean of its divisors is an integer number (2682048).

Almost surely, 2^18187421 is an apocalyptic number.

It is an amenable number.

18187421 is a deficient number, since it is larger than the sum of its proper divisors (3268963).

18187421 is an equidigital number, since it uses as much as digits as its factorization.

18187421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83851.

The product of its digits is 3584, while the sum is 32.

The square root of 18187421 is about 4264.6712651739. The cubic root of 18187421 is about 262.9805968134.

The spelling of 18187421 in words is "eighteen million, one hundred eighty-seven thousand, four hundred twenty-one".