21331211 has 12 divisors (see below), whose sum is σ = 24259200. Its totient is φ = 18720240.

The previous prime is 21331201. The next prime is 21331217. The reversal of 21331211 is 11213312.

It is not a de Polignac number, because 21331211 - 2⁶ = 21331147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21331217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 470 + ... + 6548.

It is an arithmetic number, because the mean of its divisors is an integer number (2021600).

Almost surely, 2^21331211 is an apocalyptic number.

21331211 is a deficient number, since it is larger than the sum of its proper divisors (2927989).

21331211 is a wasteful number, since it uses less digits than its factorization.

21331211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6130 (or 6119 counting only the distinct ones).

The product of its digits is 36, while the sum is 14.

The square root of 21331211 is about 4618.5723984799. The cubic root of 21331211 is about 277.3353122868.

Adding to 21331211 its reverse (11213312), we get a palindrome (32544523).

It can be divided in two parts, 213312 and 11, that multiplied together give a palindrome (2346432).

The spelling of 21331211 in words is "twenty-one million, three hundred thirty-one thousand, two hundred eleven".