21222011 has 4 divisors (see below), whose sum is σ = 21906624. Its totient is φ = 20537400.

The previous prime is 21221953. The next prime is 21222013. The reversal of 21222011 is 11022212.

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 21222011 - 2⁶ = 21221947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221983 and 21222001.

It is not an unprimeable number, because it can be changed into a prime (21222013) 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, 342260 + ... + 342321.

It is an arithmetic number, because the mean of its divisors is an integer number (5476656).

Almost surely, 2^21222011 is an apocalyptic number.

21222011 is a deficient number, since it is larger than the sum of its proper divisors (684613).

21222011 is an equidigital number, since it uses as much as digits as its factorization.

21222011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 684612.

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

The square root of 21222011 is about 4606.7353950493. The cubic root of 21222011 is about 276.8612519607.

Adding to 21222011 its reverse (11022212), we get a palindrome (32244223).

The spelling of 21222011 in words is "twenty-one million, two hundred twenty-two thousand, eleven".