18036221 has 8 divisors (see below), whose sum is σ = 21092544. Its totient is φ = 15099840.

The previous prime is 18036169. The next prime is 18036229. The reversal of 18036221 is 12263081.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 18036221 - 2⁶ = 18036157 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 (18036229) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29660 + ... + 30261.

It is an arithmetic number, because the mean of its divisors is an integer number (2636568).

Almost surely, 2^18036221 is an apocalyptic number.

It is an amenable number.

18036221 is a deficient number, since it is larger than the sum of its proper divisors (3056323).

18036221 is an equidigital number, since it uses as much as digits as its factorization.

18036221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59971.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 18036221 is about 4246.9072276187. The cubic root of 18036221 is about 262.2498102963.

The spelling of 18036221 in words is "eighteen million, thirty-six thousand, two hundred twenty-one".