21222011221 has 4 divisors (see below), whose sum is σ = 22338959200. Its totient is φ = 20105063244.

The previous prime is 21222011201. The next prime is 21222011249. The reversal of 21222011221 is 12211022212.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21222011221 - 2¹⁹ = 21221486933 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21222011195 and 21222011204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222011201) 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, 558473961 + ... + 558473998.

It is an arithmetic number, because the mean of its divisors is an integer number (5584739800).

Almost surely, 2^21222011221 is an apocalyptic number.

It is an amenable number.

21222011221 is a deficient number, since it is larger than the sum of its proper divisors (1116947979).

21222011221 is a wasteful number, since it uses less digits than its factorization.

21222011221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1116947978.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21222011221 its reverse (12211022212), we get a palindrome (33433033433).

The spelling of 21222011221 in words is "twenty-one billion, two hundred twenty-two million, eleven thousand, two hundred twenty-one".