21044717 has 2 divisors, whose sum is σ = 21044718. Its totient is φ = 21044716.

The previous prime is 21044711. The next prime is 21044743. The reversal of 21044717 is 71744012.

It is an a-pointer prime, because the next prime (21044743) can be obtained adding 21044717 to its sum of digits (26).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12859396 + 8185321 = 3586^2 + 2861^2 .

It is a cyclic number.

It is not a de Polignac number, because 21044717 - 2²² = 16850413 is a prime.

It is a super-2 number, since 2×21044717² = 885760227220178, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21044711) 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, 10522358 + 10522359.

It is an arithmetic number, because the mean of its divisors is an integer number (10522359).

Almost surely, 2^21044717 is an apocalyptic number.

It is an amenable number.

21044717 is a deficient number, since it is larger than the sum of its proper divisors (1).

21044717 is an equidigital number, since it uses as much as digits as its factorization.

21044717 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1568, while the sum is 26.

The square root of 21044717 is about 4587.4521250908. The cubic root of 21044717 is about 276.0881054921.

Adding to 21044717 its reverse (71744012), we get a palindrome (92788729).

The spelling of 21044717 in words is "twenty-one million, forty-four thousand, seven hundred seventeen".