18243820 has 48 divisors (see below), whose sum is σ = 44126208. Its totient is φ = 6206400.

The previous prime is 18243793. The next prime is 18243829. The reversal of 18243820 is 2834281.

18243820 is a nontrivial binomial coefficient, being equal to C(6041, 2).

It is a Harshad number since it is a multiple of its sum of digits (28).

It is not an unprimeable number, because it can be changed into a prime (18243829) 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 15 ways as a sum of consecutive naturals, for example, 20709 + ... + 21571.

It is an arithmetic number, because the mean of its divisors is an integer number (919296).

Almost surely, 2^18243820 is an apocalyptic number.

18243820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18243820 is the 6040-th triangular number.

18243820 is the 2014-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18243820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22063104).

18243820 is an abundant number, since it is smaller than the sum of its proper divisors (25882388).

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

18243820 is a wasteful number, since it uses less digits than its factorization.

18243820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1030 (or 1028 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 18243820 is about 4271.2784971247. The cubic root of 18243820 is about 263.2521496614.

The spelling of 18243820 in words is "eighteen million, two hundred forty-three thousand, eight hundred twenty".