18284421 has 4 divisors (see below), whose sum is σ = 24379232. Its totient is φ = 12189612.

The previous prime is 18284419. The next prime is 18284437. The reversal of 18284421 is 12448281.

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: 12448281 = 3 ⋅4149427.

It is not a de Polignac number, because 18284421 - 2¹ = 18284419 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 (18284411) 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, 3047401 + ... + 3047406.

It is an arithmetic number, because the mean of its divisors is an integer number (6094808).

Almost surely, 2^18284421 is an apocalyptic number.

It is an amenable number.

18284421 is a deficient number, since it is larger than the sum of its proper divisors (6094811).

18284421 is an equidigital number, since it uses as much as digits as its factorization.

18284421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6094810.

The product of its digits is 4096, while the sum is 30.

The square root of 18284421 is about 4276.0286481734. The cubic root of 18284421 is about 263.4472912034.

The spelling of 18284421 in words is "eighteen million, two hundred eighty-four thousand, four hundred twenty-one".