21126617 has 2 divisors, whose sum is σ = 21126618. Its totient is φ = 21126616.

The previous prime is 21126607. The next prime is 21126629. The reversal of 21126617 is 71662112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19219456 + 1907161 = 4384^2 + 1381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21126617 - 2⁴ = 21126601 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21126607) 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 as a sum of consecutive naturals, namely, 10563308 + 10563309.

It is an arithmetic number, because the mean of its divisors is an integer number (10563309).

Almost surely, 2^21126617 is an apocalyptic number.

It is an amenable number.

21126617 is a deficient number, since it is larger than the sum of its proper divisors (1).

21126617 is an equidigital number, since it uses as much as digits as its factorization.

21126617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 26.

The square root of 21126617 is about 4596.3699807566. The cubic root of 21126617 is about 276.4457937812.

Adding to 21126617 its reverse (71662112), we get a palindrome (92788729).

The spelling of 21126617 in words is "twenty-one million, one hundred twenty-six thousand, six hundred seventeen".