21213222 has 16 divisors (see below), whose sum is σ = 44271360. Its totient is φ = 6763592.

The previous prime is 21213193. The next prime is 21213251. The reversal of 21213222 is 22231212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21213193) and next prime (21213251).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76722 + ... + 76997.

It is an arithmetic number, because the mean of its divisors is an integer number (2766960).

Almost surely, 2^21213222 is an apocalyptic number.

21213222 is an abundant number, since it is smaller than the sum of its proper divisors (23058138).

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

21213222 is a wasteful number, since it uses less digits than its factorization.

21213222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153747.

The product of its digits is 96, while the sum is 15.

The square root of 21213222 is about 4605.7813669344. The cubic root of 21213222 is about 276.8230264042.

Adding to 21213222 its reverse (22231212), we get a palindrome (43444434).

The spelling of 21213222 in words is "twenty-one million, two hundred thirteen thousand, two hundred twenty-two".