21222111 has 8 divisors (see below), whose sum is σ = 28470400. Its totient is φ = 14060952.

The previous prime is 21222043. The next prime is 21222143. The reversal of 21222111 is 11122212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21222111 - 2¹³ = 21213919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222181) 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, 21211 + ... + 22188.

It is an arithmetic number, because the mean of its divisors is an integer number (3558800).

Almost surely, 2^21222111 is an apocalyptic number.

21222111 is a deficient number, since it is larger than the sum of its proper divisors (7248289).

21222111 is a wasteful number, since it uses less digits than its factorization.

21222111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43565.

The product of its digits is 16, while the sum is 12.

The square root of 21222111 is about 4606.7462487096. The cubic root of 21222111 is about 276.8616868249.

Adding to 21222111 its reverse (11122212), we get a palindrome (32344323).

It can be divided in two parts, 2122211 and 1, that added together give a palindrome (2122212).

The spelling of 21222111 in words is "twenty-one million, two hundred twenty-two thousand, one hundred eleven".