21112217 has 4 divisors (see below), whose sum is σ = 24128256. Its totient is φ = 18096180.

The previous prime is 21112207. The next prime is 21112241. The reversal of 21112217 is 71221112.

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 21112217 - 2¹⁶ = 21046681 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112195 and 21112204.

It is not an unprimeable number, because it can be changed into a prime (21112207) 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, 1508009 + ... + 1508022.

It is an arithmetic number, because the mean of its divisors is an integer number (6032064).

Almost surely, 2^21112217 is an apocalyptic number.

It is an amenable number.

21112217 is a deficient number, since it is larger than the sum of its proper divisors (3016039).

21112217 is an equidigital number, since it uses as much as digits as its factorization.

21112217 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3016038.

The product of its digits is 56, while the sum is 17.

The square root of 21112217 is about 4594.8032602060. The cubic root of 21112217 is about 276.3829705944.

Adding to 21112217 its reverse (71221112), we get a palindrome (92333329).

The spelling of 21112217 in words is "twenty-one million, one hundred twelve thousand, two hundred seventeen".