21022211221 has 8 divisors (see below), whose sum is σ = 23033469600. Its totient is φ = 19027644240.

The previous prime is 21022211213. The next prime is 21022211239. The reversal of 21022211221 is 12211222012.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21022211221 - 2³ = 21022211213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21022211195 and 21022211204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21022211201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4170211 + ... + 4175248.

It is an arithmetic number, because the mean of its divisors is an integer number (2879183700).

Almost surely, 2^21022211221 is an apocalyptic number.

It is an amenable number.

21022211221 is a deficient number, since it is larger than the sum of its proper divisors (2011258379).

21022211221 is a wasteful number, since it uses less digits than its factorization.

21022211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8345699.

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

Adding to 21022211221 its reverse (12211222012), we get a palindrome (33233433233).

The spelling of 21022211221 in words is "twenty-one billion, twenty-two million, two hundred eleven thousand, two hundred twenty-one".