21432317 has 2 divisors, whose sum is σ = 21432318. Its totient is φ = 21432316.

The previous prime is 21432311. The next prime is 21432331. The reversal of 21432317 is 71323412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15952036 + 5480281 = 3994^2 + 2341^2 .

It is a cyclic number.

It is not a de Polignac number, because 21432317 - 2¹² = 21428221 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21432292 and 21432301.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21432311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10716158 + 10716159.

It is an arithmetic number, because the mean of its divisors is an integer number (10716159).

Almost surely, 2^21432317 is an apocalyptic number.

It is an amenable number.

21432317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21432317 is an equidigital number, since it uses as much as digits as its factorization.

21432317 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 23.

The square root of 21432317 is about 4629.5050491386. The cubic root of 21432317 is about 277.7727945358.

Adding to 21432317 its reverse (71323412), we get a palindrome (92755729).

The spelling of 21432317 in words is "twenty-one million, four hundred thirty-two thousand, three hundred seventeen".