21804718 has 24 divisors (see below), whose sum is σ = 36576576. Its totient is φ = 9734400.

The previous prime is 21804701. The next prime is 21804719. The reversal of 21804718 is 81740812.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a self number, because there is not a number n which added to its sum of digits gives 21804718.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21804719) 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, 9438 + ... + 11518.

It is an arithmetic number, because the mean of its divisors is an integer number (1524024).

Almost surely, 2^21804718 is an apocalyptic number.

21804718 is a deficient number, since it is larger than the sum of its proper divisors (14771858).

21804718 is a wasteful number, since it uses less digits than its factorization.

21804718 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2140 (or 2127 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 31.

The square root of 21804718 is about 4669.5522269271. The cubic root of 21804718 is about 279.3723953299.

It can be divided in two parts, 21804 and 718, that added together give a palindrome (22522).

The spelling of 21804718 in words is "twenty-one million, eight hundred four thousand, seven hundred eighteen".