21220221120221 has 8 divisors (see below), whose sum is σ = 21552356489400. Its totient is φ = 20890168104960.

The previous prime is 21220221120209. The next prime is 21220221120253. The reversal of 21220221120221 is 12202112202212.

It can be written as a sum of positive squares in 4 ways, for example, as 9536546896900 + 11683674223321 = 3088130^2 + 3418139^2 .

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 21220221120221 - 2³⁴ = 21203041251037 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21220221120193 and 21220221120202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220221120421) 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, 520567940 + ... + 520608701.

It is an arithmetic number, because the mean of its divisors is an integer number (2694044561175).

Almost surely, 2^{21220221120221} is an apocalyptic number.

It is an amenable number.

21220221120221 is a deficient number, since it is larger than the sum of its proper divisors (332135369179).

21220221120221 is a wasteful number, since it uses less digits than its factorization.

21220221120221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1041176959.

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 21220221120221 its reverse (12202112202212), we get a palindrome (33422333322433).

The spelling of 21220221120221 in words is "twenty-one trillion, two hundred twenty billion, two hundred twenty-one million, one hundred twenty thousand, two hundred twenty-one".