21211222020221 has 4 divisors (see below), whose sum is σ = 21213923062332. Its totient is φ = 21208520978112.

The previous prime is 21211222020199. The next prime is 21211222020227. The reversal of 21211222020221 is 12202022211212.

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 682257828121 + 20528964192100 = 825989^2 + 4530890^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21211222020221 is a prime.

It is a super-2 number, since 2×21211222020221² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21211222020193 and 21211222020202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211222020227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1350509276 + ... + 1350524981.

It is an arithmetic number, because the mean of its divisors is an integer number (5303480765583).

Almost surely, 2^{21211222020221} is an apocalyptic number.

It is an amenable number.

21211222020221 is a deficient number, since it is larger than the sum of its proper divisors (2701042111).

21211222020221 is an equidigital number, since it uses as much as digits as its factorization.

21211222020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2701042110.

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

Adding to 21211222020221 its reverse (12202022211212), we get a palindrome (33413244231433).

The spelling of 21211222020221 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-two million, twenty thousand, two hundred twenty-one".