21112117 has 4 divisors (see below), whose sum is σ = 22736140. Its totient is φ = 19488096.

The previous prime is 21112103. The next prime is 21112121. The reversal of 21112117 is 71121112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10182481 + 10929636 = 3191^2 + 3306^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112117 - 2²³ = 12723509 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21112117.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112127) 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, 811992 + ... + 812017.

It is an arithmetic number, because the mean of its divisors is an integer number (5684035).

Almost surely, 2^21112117 is an apocalyptic number.

It is an amenable number.

21112117 is a deficient number, since it is larger than the sum of its proper divisors (1624023).

21112117 is a wasteful number, since it uses less digits than its factorization.

21112117 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1624022.

The product of its digits is 28, while the sum is 16.

The square root of 21112117 is about 4594.7923783344. The cubic root of 21112117 is about 276.3825342224.

Adding to 21112117 its reverse (71121112), we get a palindrome (92233229).

The spelling of 21112117 in words is "twenty-one million, one hundred twelve thousand, one hundred seventeen".