21112220221 has 8 divisors (see below), whose sum is σ = 21152533824. Its totient is φ = 21071930880.

The previous prime is 21112220209. The next prime is 21112220243. The reversal of 21112220221 is 12202221112.

It is a happy number.

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 21112220221 - 2²³ = 21103831613 is a prime.

It is a super-4 number, since 4×21112220221⁴ (a number of 42 digits) contains 4444 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112220195 and 21112220204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112220251) 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 7 ways as a sum of consecutive naturals, for example, 3511600 + ... + 3517606.

It is an arithmetic number, because the mean of its divisors is an integer number (2644066728).

Almost surely, 2^21112220221 is an apocalyptic number.

It is an amenable number.

21112220221 is a deficient number, since it is larger than the sum of its proper divisors (40313603).

21112220221 is an equidigital number, since it uses as much as digits as its factorization.

21112220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12131.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21112220221 its reverse (12202221112), we get a palindrome (33314441333).

The spelling of 21112220221 in words is "twenty-one billion, one hundred twelve million, two hundred twenty thousand, two hundred twenty-one".