18818920 has 16 divisors (see below), whose sum is σ = 42342660. Its totient is φ = 7527552.

The previous prime is 18818909. The next prime is 18818923. The reversal of 18818920 is 2981881.

It can be written as a sum of positive squares in 2 ways, for example, as 18818244 + 676 = 4338^2 + 26^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18818920.

It is not an unprimeable number, because it can be changed into a prime (18818923) 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 3 ways as a sum of consecutive naturals, for example, 235197 + ... + 235276.

Almost surely, 2^18818920 is an apocalyptic number.

18818920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18818920 is an abundant number, since it is smaller than the sum of its proper divisors (23523740).

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

18818920 is a wasteful number, since it uses less digits than its factorization.

18818920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 470484 (or 470480 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 37.

The square root of 18818920 is about 4338.0779153906. The cubic root of 18818920 is about 265.9897484130.

It can be divided in two parts, 1881 and 8920, that added together give a palindrome (10801).

The spelling of 18818920 in words is "eighteen million, eight hundred eighteen thousand, nine hundred twenty".