18818820 has 36 divisors (see below), whose sum is σ = 57084300. Its totient is φ = 5018304.

The previous prime is 18818809. The next prime is 18818831. The reversal of 18818820 is 2881881.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (18818809) and next prime (18818831).

It can be written as a sum of positive squares in 2 ways, for example, as 6874884 + 11943936 = 2622^2 + 3456^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 52095 + ... + 52454.

It is an arithmetic number, because the mean of its divisors is an integer number (1585675).

Almost surely, 2^18818820 is an apocalyptic number.

18818820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18818820 is an abundant number, since it is smaller than the sum of its proper divisors (38265480).

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

18818820 is a wasteful number, since it uses less digits than its factorization.

18818820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 104564 (or 104559 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 36.

The square root of 18818820 is about 4338.0663895335. The cubic root of 18818820 is about 265.9892772733.

It can be divided in two parts, 1881 and 8820, that added together give a palindrome (10701).

The spelling of 18818820 in words is "eighteen million, eight hundred eighteen thousand, eight hundred twenty".