21650017 has 2 divisors, whose sum is σ = 21650018. Its totient is φ = 21650016.

The previous prime is 21650011. The next prime is 21650021. The reversal of 21650017 is 71005612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20034576 + 1615441 = 4476^2 + 1271^2 .

It is a cyclic number.

It is not a de Polignac number, because 21650017 - 2¹⁵ = 21617249 is a prime.

It is a super-2 number, since 2×21650017² = 937446472200578, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21650017.

It is not a weakly prime, because it can be changed into another prime (21650011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10825008 + 10825009.

It is an arithmetic number, because the mean of its divisors is an integer number (10825009).

Almost surely, 2^21650017 is an apocalyptic number.

It is an amenable number.

21650017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21650017 is an equidigital number, since it uses as much as digits as its factorization.

21650017 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 21650017 is about 4652.9578764481. The cubic root of 21650017 is about 278.7101257422.

Adding to 21650017 its reverse (71005612), we get a palindrome (92655629).

The spelling of 21650017 in words is "twenty-one million, six hundred fifty thousand, seventeen".