18199820 has 24 divisors (see below), whose sum is σ = 39538800. Its totient is φ = 7028672.

The previous prime is 18199801. The next prime is 18199823. The reversal of 18199820 is 2899181.

It is not an unprimeable number, because it can be changed into a prime (18199823) 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 7 ways as a sum of consecutive naturals, for example, 15110 + ... + 16269.

It is an arithmetic number, because the mean of its divisors is an integer number (1647450).

Almost surely, 2^18199820 is an apocalyptic number.

18199820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18199820 is an abundant number, since it is smaller than the sum of its proper divisors (21338980).

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

18199820 is a wasteful number, since it uses less digits than its factorization.

18199820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31417 (or 31415 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 18199820 is about 4266.1247051628. The cubic root of 18199820 is about 263.0403442569.

It can be divided in two parts, 181 and 99820, that added together give a palindrome (100001).

The spelling of 18199820 in words is "eighteen million, one hundred ninety-nine thousand, eight hundred twenty".