21220121220101 has 4 divisors (see below), whose sum is σ = 21221053217100. Its totient is φ = 21219189223104.

The previous prime is 21220121220083. The next prime is 21220121220107. The reversal of 21220121220101 is 10102212102212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4791480213025 + 16428641007076 = 2188945^2 + 4053226^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220121220101 - 2³⁴ = 21202941350917 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21220121220101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220121220107) 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, 465964346 + ... + 466009883.

It is an arithmetic number, because the mean of its divisors is an integer number (5305263304275).

Almost surely, 2^{21220121220101} is an apocalyptic number.

It is an amenable number.

21220121220101 is a deficient number, since it is larger than the sum of its proper divisors (931996999).

21220121220101 is an equidigital number, since it uses as much as digits as its factorization.

21220121220101 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 931996998.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21220121220101 its reverse (10102212102212), we get a palindrome (31322333322313).

The spelling of 21220121220101 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, two hundred twenty thousand, one hundred one".