18331820 has 24 divisors (see below), whose sum is σ = 41458704. Its totient is φ = 6768576.

The previous prime is 18331813. The next prime is 18331829. The reversal of 18331820 is 2813381.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a self number, because there is not a number n which added to its sum of digits gives 18331820.

It is not an unprimeable number, because it can be changed into a prime (18331829) 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 in 7 ways as a sum of consecutive naturals, for example, 34994 + ... + 35513.

It is an arithmetic number, because the mean of its divisors is an integer number (1727446).

Almost surely, 2^18331820 is an apocalyptic number.

18331820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18331820 is an abundant number, since it is smaller than the sum of its proper divisors (23126884).

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

18331820 is a wasteful number, since it uses less digits than its factorization.

18331820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70529 (or 70527 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 18331820 is about 4281.5674699811. The cubic root of 18331820 is about 263.6747409991.

The spelling of 18331820 in words is "eighteen million, three hundred thirty-one thousand, eight hundred twenty".