21122201221 has 4 divisors (see below), whose sum is σ = 23042401344. Its totient is φ = 19202001100.

The previous prime is 21122201197. The next prime is 21122201227. The reversal of 21122201221 is 12210222112.

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 21122201221 - 2¹⁵ = 21122168453 is a prime.

It is a super-2 number, since 2×21122201221² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21122201195 and 21122201204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122201227) 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, 960100045 + ... + 960100066.

It is an arithmetic number, because the mean of its divisors is an integer number (5760600336).

Almost surely, 2^21122201221 is an apocalyptic number.

It is an amenable number.

21122201221 is a deficient number, since it is larger than the sum of its proper divisors (1920200123).

21122201221 is a wasteful number, since it uses less digits than its factorization.

21122201221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1920200122.

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

Adding to 21122201221 its reverse (12210222112), we get a palindrome (33332423333).

The spelling of 21122201221 in words is "twenty-one billion, one hundred twenty-two million, two hundred one thousand, two hundred twenty-one".