18210820 has 24 divisors (see below), whose sum is σ = 38367000. Its totient is φ = 7260672.

The previous prime is 18210817. The next prime is 18210821. The reversal of 18210820 is 2801281.

It can be written as a sum of positive squares in 4 ways, for example, as 3218436 + 14992384 = 1794^2 + 3872^2 .

It is a junction number, because it is equal to n+sod(n) for n = 18210791 and 18210800.

It is not an unprimeable number, because it can be changed into a prime (18210821) 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, 5676 + ... + 8284.

It is an arithmetic number, because the mean of its divisors is an integer number (1598625).

Almost surely, 2^18210820 is an apocalyptic number.

18210820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18210820 is an abundant number, since it is smaller than the sum of its proper divisors (20156180).

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

18210820 is a wasteful number, since it uses less digits than its factorization.

18210820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2967 (or 2965 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 18210820 is about 4267.4137366794. The cubic root of 18210820 is about 263.0933275840.

The spelling of 18210820 in words is "eighteen million, two hundred ten thousand, eight hundred twenty".