21617111 has 2 divisors, whose sum is σ = 21617112. Its totient is φ = 21617110.

The previous prime is 21617053. The next prime is 21617143. The reversal of 21617111 is 11171612.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21617111 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21617191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10808555 + 10808556.

It is an arithmetic number, because the mean of its divisors is an integer number (10808556).

Almost surely, 2^21617111 is an apocalyptic number.

21617111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21617111 is an equidigital number, since it uses as much as digits as its factorization.

21617111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84, while the sum is 20.

The square root of 21617111 is about 4649.4205015249. The cubic root of 21617111 is about 278.5688497053.

Adding to 21617111 its reverse (11171612), we get a palindrome (32788723).

The spelling of 21617111 in words is "twenty-one million, six hundred seventeen thousand, one hundred eleven".