21226218 has 16 divisors (see below), whose sum is σ = 45718176. Its totient is φ = 6531120.

The previous prime is 21226213. The next prime is 21226237. The reversal of 21226218 is 81262212.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21226213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 135988 + ... + 136143.

It is an arithmetic number, because the mean of its divisors is an integer number (2857386).

Almost surely, 2^21226218 is an apocalyptic number.

21226218 is an abundant number, since it is smaller than the sum of its proper divisors (24491958).

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

21226218 is a wasteful number, since it uses less digits than its factorization.

21226218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 272149.

The product of its digits is 768, while the sum is 24.

The square root of 21226218 is about 4607.1919864490. The cubic root of 21226218 is about 276.8795455197.

The spelling of 21226218 in words is "twenty-one million, two hundred twenty-six thousand, two hundred eighteen".