21110120212221 has 12 divisors (see below), whose sum is σ = 30762240074748. Its totient is φ = 13948869992064.

The previous prime is 21110120212217. The next prime is 21110120212231. The reversal of 21110120212221 is 12221202101112.

21110120212221 is a `hidden beast` number, since 2 + 1 + 110 + 120 + 212 + 221 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 95551464996 + 21014568747225 = 309114^2 + 4584165^2 .

It is not a de Polignac number, because 21110120212221 - 2² = 21110120212217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21110120212194 and 21110120212203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110120212211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10378622490 + ... + 10378624523.

It is an arithmetic number, because the mean of its divisors is an integer number (2563520006229).

Almost surely, 2^{21110120212221} is an apocalyptic number.

It is an amenable number.

21110120212221 is a deficient number, since it is larger than the sum of its proper divisors (9652119862527).

21110120212221 is a wasteful number, since it uses less digits than its factorization.

21110120212221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20757247132 (or 20757247129 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21110120212221 its reverse (12221202101112), we get a palindrome (33331322313333).

The spelling of 21110120212221 in words is "twenty-one trillion, one hundred ten billion, one hundred twenty million, two hundred twelve thousand, two hundred twenty-one".