18021187 has 2 divisors, whose sum is σ = 18021188. Its totient is φ = 18021186.

The previous prime is 18021131. The next prime is 18021193. The reversal of 18021187 is 78112081.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18021187 - 2¹⁵ = 17988419 is a prime.

It is not a weakly prime, because it can be changed into another prime (18021197) 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 as a sum of consecutive naturals, namely, 9010593 + 9010594.

It is an arithmetic number, because the mean of its divisors is an integer number (9010594).

Almost surely, 2^18021187 is an apocalyptic number.

18021187 is a deficient number, since it is larger than the sum of its proper divisors (1).

18021187 is an equidigital number, since it uses as much as digits as its factorization.

18021187 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 18021187 is about 4245.1368646959. The cubic root of 18021187 is about 262.1769243775.

The spelling of 18021187 in words is "eighteen million, twenty-one thousand, one hundred eighty-seven".