18216020 has 24 divisors (see below), whose sum is σ = 38356584. Its totient is φ = 7266816.

The previous prime is 18216017. The next prime is 18216043. The reversal of 18216020 is 2061281.

It can be written as a sum of positive squares in 4 ways, for example, as 6615184 + 11600836 = 2572^2 + 3406^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 18215983 and 18216001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8144 + ... + 10136.

It is an arithmetic number, because the mean of its divisors is an integer number (1598191).

Almost surely, 2^18216020 is an apocalyptic number.

18216020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18216020 is an abundant number, since it is smaller than the sum of its proper divisors (20140564).

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

18216020 is a wasteful number, since it uses less digits than its factorization.

18216020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2459 (or 2457 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 18216020 is about 4268.0229615127. The cubic root of 18216020 is about 263.1183668209.

The spelling of 18216020 in words is "eighteen million, two hundred sixteen thousand, twenty".