18008820 has 36 divisors (see below), whose sum is σ = 54627300. Its totient is φ = 4802304.

The previous prime is 18008819. The next prime is 18008821. The reversal of 18008820 is 2880081.

It is an interprime number because it is at equal distance from previous prime (18008819) and next prime (18008821).

It can be written as a sum of positive squares in 2 ways, for example, as 2232036 + 15776784 = 1494^2 + 3972^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18008821) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 49845 + ... + 50204.

It is an arithmetic number, because the mean of its divisors is an integer number (1517425).

Almost surely, 2^18008820 is an apocalyptic number.

18008820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18008820 is an abundant number, since it is smaller than the sum of its proper divisors (36618480).

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

18008820 is a wasteful number, since it uses less digits than its factorization.

18008820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100064 (or 100059 counting only the distinct ones).

The product of its (nonzero) digits is 1024, while the sum is 27.

The square root of 18008820 is about 4243.6800067866. The cubic root of 18008820 is about 262.1169378740.

The spelling of 18008820 in words is "eighteen million, eight thousand, eight hundred twenty".