18021000 has 64 divisors (see below), whose sum is σ = 56234880. Its totient is φ = 4804800.

The previous prime is 18020993. The next prime is 18021053. The reversal of 18021000 is 12081.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 4 + ... + 6003.

It is an arithmetic number, because the mean of its divisors is an integer number (878670).

Almost surely, 2^18021000 is an apocalyptic number.

18021000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18021000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28117440).

18021000 is an abundant number, since it is smaller than the sum of its proper divisors (38213880).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18021000 is a wasteful number, since it uses less digits than its factorization.

18021000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6031 (or 6017 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 18021000 is about 4245.1148394360. The cubic root of 18021000 is about 262.1760175328.

Adding to 18021000 its reverse (12081), we get a palindrome (18033081).

The spelling of 18021000 in words is "eighteen million, twenty-one thousand".