18023820 has 24 divisors (see below), whose sum is σ = 50466864. Its totient is φ = 4806336.

The previous prime is 18023801. The next prime is 18023821. The reversal of 18023820 is 2832081.

It is not an unprimeable number, because it can be changed into a prime (18023821) 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, 150139 + ... + 150258.

It is an arithmetic number, because the mean of its divisors is an integer number (2102786).

Almost surely, 2^18023820 is an apocalyptic number.

18023820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18023820 is an abundant number, since it is smaller than the sum of its proper divisors (32443044).

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

18023820 is a wasteful number, since it uses less digits than its factorization.

18023820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 300409 (or 300407 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 18023820 is about 4245.4469729347. The cubic root of 18023820 is about 262.1896922791.

The spelling of 18023820 in words is "eighteen million, twenty-three thousand, eight hundred twenty".