21223211 has 4 divisors (see below), whose sum is σ = 21233352. Its totient is φ = 21213072.

The previous prime is 21223193. The next prime is 21223219. The reversal of 21223211 is 11232212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21223211 - 2¹⁴ = 21206827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21223219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 641 + ... + 6546.

It is an arithmetic number, because the mean of its divisors is an integer number (5308338).

Almost surely, 2^21223211 is an apocalyptic number.

21223211 is a deficient number, since it is larger than the sum of its proper divisors (10141).

21223211 is an equidigital number, since it uses as much as digits as its factorization.

21223211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10140.

The product of its digits is 48, while the sum is 14.

The square root of 21223211 is about 4606.8656372853. The cubic root of 21223211 is about 276.8664702415.

Adding to 21223211 its reverse (11232212), we get a palindrome (32455423).

Subtracting from 21223211 its reverse (11232212), we obtain a palindrome (9990999).

The spelling of 21223211 in words is "twenty-one million, two hundred twenty-three thousand, two hundred eleven".