21220101212221 has 4 divisors (see below), whose sum is σ = 21223238894752. Its totient is φ = 21216963529692.

The previous prime is 21220101212213. The next prime is 21220101212227. The reversal of 21220101212221 is 12221210102212.

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 21220101212221 - 2³ = 21220101212213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220101212227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1568831121 + ... + 1568844646.

It is an arithmetic number, because the mean of its divisors is an integer number (5305809723688).

Almost surely, 2^{21220101212221} is an apocalyptic number.

It is an amenable number.

21220101212221 is a deficient number, since it is larger than the sum of its proper divisors (3137682531).

21220101212221 is an equidigital number, since it uses as much as digits as its factorization.

21220101212221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3137682530.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21220101212221 its reverse (12221210102212), we get a palindrome (33441311314433).

The spelling of 21220101212221 in words is "twenty-one trillion, two hundred twenty billion, one hundred one million, two hundred twelve thousand, two hundred twenty-one".