18021311 has 8 divisors (see below), whose sum is σ = 22468224. Its totient is φ = 14042520.

The previous prime is 18021307. The next prime is 18021319. The reversal of 18021311 is 11312081.

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 18021311 - 2² = 18021307 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18021311.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18021319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116945 + ... + 117098.

It is an arithmetic number, because the mean of its divisors is an integer number (2808528).

Almost surely, 2^18021311 is an apocalyptic number.

18021311 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

18021311 is a deficient number, since it is larger than the sum of its proper divisors (4446913).

18021311 is a wasteful number, since it uses less digits than its factorization.

18021311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 234061.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 18021311 is about 4245.1514696180. The cubic root of 18021311 is about 262.1775257042.

Adding to 18021311 its reverse (11312081), we get a palindrome (29333392).

It can be divided in two parts, 1802 and 1311, that added together give a palindrome (3113).

The spelling of 18021311 in words is "eighteen million, twenty-one thousand, three hundred eleven".