21221222211 has 64 divisors (see below), whose sum is σ = 36696499200. Its totient is φ = 11870496000.

The previous prime is 21221222201. The next prime is 21221222219. The reversal of 21221222211 is 11222212212.

It is a happy number.

21221222211 is a `hidden beast` number, since 212 + 21 + 222 + 211 = 666.

It is not a de Polignac number, because 21221222211 - 2⁶ = 21221222147 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21221222219) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1692676 + ... + 1705166.

It is an arithmetic number, because the mean of its divisors is an integer number (573382800).

Almost surely, 2^21221222211 is an apocalyptic number.

21221222211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21221222211 is a deficient number, since it is larger than the sum of its proper divisors (15475276989).

21221222211 is a wasteful number, since it uses less digits than its factorization.

21221222211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12697 (or 12691 counting only the distinct ones).

The product of its digits is 128, while the sum is 18.

Adding to 21221222211 its reverse (11222212212), we get a palindrome (32443434423).

Subtracting from 21221222211 its reverse (11222212212), we obtain a palindrome (9999009999).

The spelling of 21221222211 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, two hundred eleven".