21110021222221 has 4 divisors (see below), whose sum is σ = 21364358827392. Its totient is φ = 20855683617052.

The previous prime is 21110021222197. The next prime is 21110021222237. The reversal of 21110021222221 is 12222212001112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21110021222221 - 2¹¹ = 21110021220173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110021262221) 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, 127168802461 + ... + 127168802626.

It is an arithmetic number, because the mean of its divisors is an integer number (5341089706848).

Almost surely, 2^{21110021222221} is an apocalyptic number.

It is an amenable number.

21110021222221 is a deficient number, since it is larger than the sum of its proper divisors (254337605171).

21110021222221 is an equidigital number, since it uses as much as digits as its factorization.

21110021222221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254337605170.

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21110021222221 its reverse (12222212001112), we get a palindrome (33332233223333).

The spelling of 21110021222221 in words is "twenty-one trillion, one hundred ten billion, twenty-one million, two hundred twenty-two thousand, two hundred twenty-one".