21394218 has 16 divisors (see below), whose sum is σ = 43037856. Its totient is φ = 7089840.

The previous prime is 21394213. The next prime is 21394229. The reversal of 21394218 is 81249312.

It is not an unprimeable number, because it can be changed into a prime (21394213) 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, 9268 + ... + 11343.

It is an arithmetic number, because the mean of its divisors is an integer number (2689866).

Almost surely, 2^21394218 is an apocalyptic number.

21394218 is an abundant number, since it is smaller than the sum of its proper divisors (21643638).

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

21394218 is a wasteful number, since it uses less digits than its factorization.

21394218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20789.

The product of its digits is 3456, while the sum is 30.

The square root of 21394218 is about 4625.3884161225. The cubic root of 21394218 is about 277.6081033244.

It can be divided in two parts, 21394 and 218, that added together give a palindrome (21612).

The spelling of 21394218 in words is "twenty-one million, three hundred ninety-four thousand, two hundred eighteen".