18280720 has 20 divisors (see below), whose sum is σ = 42502860. Its totient is φ = 7312256.

The previous prime is 18280709. The next prime is 18280721. The reversal of 18280720 is 2708281.

It can be written as a sum of positive squares in 2 ways, for example, as 14470416 + 3810304 = 3804^2 + 1952^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (18280721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114175 + ... + 114334.

It is an arithmetic number, because the mean of its divisors is an integer number (2125143).

Almost surely, 2^18280720 is an apocalyptic number.

18280720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18280720 is an abundant number, since it is smaller than the sum of its proper divisors (24222140).

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

18280720 is a wasteful number, since it uses less digits than its factorization.

18280720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228522 (or 228516 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 18280720 is about 4275.5958649058. The cubic root of 18280720 is about 263.4295149734.

The spelling of 18280720 in words is "eighteen million, two hundred eighty thousand, seven hundred twenty".