21022211 has 4 divisors (see below), whose sum is σ = 24025392. Its totient is φ = 18019032.

The previous prime is 21022193. The next prime is 21022213. The reversal of 21022211 is 11222012.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21022211 - 2¹⁴ = 21005827 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21022192 and 21022201.

It is not an unprimeable number, because it can be changed into a prime (21022213) 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, 1501580 + ... + 1501593.

It is an arithmetic number, because the mean of its divisors is an integer number (6006348).

Almost surely, 2^21022211 is an apocalyptic number.

21022211 is a deficient number, since it is larger than the sum of its proper divisors (3003181).

21022211 is an equidigital number, since it uses as much as digits as its factorization.

21022211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3003180.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21022211 is about 4584.9984732822. The cubic root of 21022211 is about 275.9896507707.

Adding to 21022211 its reverse (11222012), we get a palindrome (32244223).

The spelling of 21022211 in words is "twenty-one million, twenty-two thousand, two hundred eleven".