21221222011221 has 8 divisors (see below), whose sum is σ = 29270651050080. Its totient is φ = 13659637156592.

The previous prime is 21221222011021. The next prime is 21221222011303. The reversal of 21221222011221 is 12211022212212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221222011221 - 2³⁵ = 21186862272853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221222011021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 121961045955 + ... + 121961046128.

It is an arithmetic number, because the mean of its divisors is an integer number (3658831381260).

Almost surely, 2^{21221222011221} is an apocalyptic number.

It is an amenable number.

21221222011221 is a deficient number, since it is larger than the sum of its proper divisors (8049429038859).

21221222011221 is a wasteful number, since it uses less digits than its factorization.

21221222011221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243922092115.

The product of its (nonzero) digits is 256, while the sum is 21.

Adding to 21221222011221 its reverse (12211022212212), we get a palindrome (33432244223433).

The spelling of 21221222011221 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty-two million, eleven thousand, two hundred twenty-one".