21203317 has 2 divisors, whose sum is σ = 21203318. Its totient is φ = 21203316.

The previous prime is 21203293. The next prime is 21203341. The reversal of 21203317 is 71330212.

It is a balanced prime because it is at equal distance from previous prime (21203293) and next prime (21203341).

It can be written as a sum of positive squares in only one way, i.e., 20439441 + 763876 = 4521^2 + 874^2 .

It is a cyclic number.

It is not a de Polignac number, because 21203317 - 2²³ = 12814709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21203294 and 21203303.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21203717) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601658 + 10601659.

It is an arithmetic number, because the mean of its divisors is an integer number (10601659).

Almost surely, 2^21203317 is an apocalyptic number.

It is an amenable number.

21203317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21203317 is an equidigital number, since it uses as much as digits as its factorization.

21203317 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 252, while the sum is 19.

The square root of 21203317 is about 4604.7059623824. The cubic root of 21203317 is about 276.7799344284.

Adding to 21203317 its reverse (71330212), we get a palindrome (92533529).

The spelling of 21203317 in words is "twenty-one million, two hundred three thousand, three hundred seventeen".