21222166 has 32 divisors (see below), whose sum is σ = 37988352. Its totient is φ = 8700480.

The previous prime is 21222163. The next prime is 21222181. The reversal of 21222166 is 66122212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 46210 + ... + 46666.

It is an arithmetic number, because the mean of its divisors is an integer number (1187136).

Almost surely, 2^21222166 is an apocalyptic number.

21222166 is a deficient number, since it is larger than the sum of its proper divisors (16766186).

21222166 is a wasteful number, since it uses less digits than its factorization.

21222166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604.

The product of its digits is 576, while the sum is 22.

The square root of 21222166 is about 4606.7522182119. The cubic root of 21222166 is about 276.8619259997.

Adding to 21222166 its reverse (66122212), we get a palindrome (87344378).

The spelling of 21222166 in words is "twenty-one million, two hundred twenty-two thousand, one hundred sixty-six".