18421287 has 4 divisors (see below), whose sum is σ = 24561720. Its totient is φ = 12280856.

The previous prime is 18421237. The next prime is 18421297. The reversal of 18421287 is 78212481.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18421287 - 2¹⁸ = 18159143 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18421237) 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 3 ways as a sum of consecutive naturals, for example, 3070212 + ... + 3070217.

It is an arithmetic number, because the mean of its divisors is an integer number (6140430).

Almost surely, 2^18421287 is an apocalyptic number.

18421287 is a deficient number, since it is larger than the sum of its proper divisors (6140433).

18421287 is an equidigital number, since it uses as much as digits as its factorization.

18421287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6140432.

The product of its digits is 7168, while the sum is 33.

The square root of 18421287 is about 4292.0026794027. The cubic root of 18421287 is about 264.1029929873.

The spelling of 18421287 in words is "eighteen million, four hundred twenty-one thousand, two hundred eighty-seven".