21220111 has 8 divisors (see below), whose sum is σ = 23443200. Its totient is φ = 19046040.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220111 is 11102212.

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 21220111 - 2¹ = 21220109 is a prime.

It is a super-2 number, since 2×21220111² = 900586221704642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21220211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11341 + ... + 13078.

It is an arithmetic number, because the mean of its divisors is an integer number (2930400).

Almost surely, 2^21220111 is an apocalyptic number.

21220111 is a deficient number, since it is larger than the sum of its proper divisors (2223089).

21220111 is a wasteful number, since it uses less digits than its factorization.

21220111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24509.

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

The square root of 21220111 is about 4606.5291706446. The cubic root of 21220111 is about 276.8529892804.

Adding to 21220111 its reverse (11102212), we get a palindrome (32322323).

It can be divided in two parts, 212201 and 11, that added together give a palindrome (212212).

The spelling of 21220111 in words is "twenty-one million, two hundred twenty thousand, one hundred eleven".