21202221122221 has 8 divisors (see below), whose sum is σ = 21236766636960. Its totient is φ = 21167681959152.

The previous prime is 21202221122179. The next prime is 21202221122231. The reversal of 21202221122221 is 12222112220212.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21202221122221 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21202221122192 and 21202221122201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202221122231) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5116666 + ... + 8281588.

It is an arithmetic number, because the mean of its divisors is an integer number (2654595829620).

Almost surely, 2^{21202221122221} is an apocalyptic number.

It is an amenable number.

21202221122221 is a deficient number, since it is larger than the sum of its proper divisors (34545514739).

21202221122221 is a wasteful number, since it uses less digits than its factorization.

21202221122221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3175835.

The product of its (nonzero) digits is 512, while the sum is 22.

Adding to 21202221122221 its reverse (12222112220212), we get a palindrome (33424333342433).

The spelling of 21202221122221 in words is "twenty-one trillion, two hundred two billion, two hundred twenty-one million, one hundred twenty-two thousand, two hundred twenty-one".