21012211 has 16 divisors (see below), whose sum is σ = 23904000. Its totient is φ = 18295200.

The previous prime is 21012193. The next prime is 21012227. The reversal of 21012211 is 11221012.

It is not a de Polignac number, because 21012211 - 2¹⁵ = 20979443 is a prime.

It is a super-2 number, since 2×21012211² = 883026022217042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012241) 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 15 ways as a sum of consecutive naturals, for example, 63316 + ... + 63646.

It is an arithmetic number, because the mean of its divisors is an integer number (1494000).

Almost surely, 2^21012211 is an apocalyptic number.

21012211 is a deficient number, since it is larger than the sum of its proper divisors (2891789).

21012211 is a wasteful number, since it uses less digits than its factorization.

21012211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 570.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21012211 is about 4583.9078306615. The cubic root of 21012211 is about 275.9458822340.

Adding to 21012211 its reverse (11221012), we get a palindrome (32233223).

It can be divided in two parts, 210 and 12211, that added together give a palindrome (12421).

The spelling of 21012211 in words is "twenty-one million, twelve thousand, two hundred eleven".