21222266 has 16 divisors (see below), whose sum is σ = 34846728. Its totient is φ = 9633600.

The previous prime is 21222251. The next prime is 21222269. The reversal of 21222266 is 66222212.

It can be written as a sum of positive squares in 4 ways, for example, as 4289041 + 16933225 = 2071^2 + 4115^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21222269) 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, 5105 + ... + 8276.

Almost surely, 2^21222266 is an apocalyptic number.

21222266 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21222266 is a deficient number, since it is larger than the sum of its proper divisors (13624462).

21222266 is a wasteful number, since it uses less digits than its factorization.

21222266 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13457.

The product of its digits is 1152, while the sum is 23.

The square root of 21222266 is about 4606.7630718325. The cubic root of 21222266 is about 276.8623608618.

Adding to 21222266 its reverse (66222212), we get a palindrome (87444478).

The spelling of 21222266 in words is "twenty-one million, two hundred twenty-two thousand, two hundred sixty-six".