21110221 has 8 divisors (see below), whose sum is σ = 23120064. Its totient is φ = 19115520.

The previous prime is 21110189. The next prime is 21110227. The reversal of 21110221 is 12201112.

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 21110221 - 2⁵ = 21110189 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21110198 and 21110207.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110227) 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, 756 + ... + 6541.

It is an arithmetic number, because the mean of its divisors is an integer number (2890008).

Almost surely, 2^21110221 is an apocalyptic number.

It is an amenable number.

21110221 is a deficient number, since it is larger than the sum of its proper divisors (2009843).

21110221 is a wasteful number, since it uses less digits than its factorization.

21110221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7571.

The product of its (nonzero) digits is 8, while the sum is 10.

The square root of 21110221 is about 4594.5860531717. The cubic root of 21110221 is about 276.3742603486.

Adding to 21110221 its reverse (12201112), we get a palindrome (33311333).

The spelling of 21110221 in words is "twenty-one million, one hundred ten thousand, two hundred twenty-one".