21824317 has 2 divisors, whose sum is σ = 21824318. Its totient is φ = 21824316.

The previous prime is 21824291. The next prime is 21824329. The reversal of 21824317 is 71342812.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14485636 + 7338681 = 3806^2 + 2709^2 .

It is a cyclic number.

It is not a de Polignac number, because 21824317 - 2⁷ = 21824189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21824357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10912158 + 10912159.

It is an arithmetic number, because the mean of its divisors is an integer number (10912159).

Almost surely, 2^21824317 is an apocalyptic number.

It is an amenable number.

21824317 is a deficient number, since it is larger than the sum of its proper divisors (1).

21824317 is an equidigital number, since it uses as much as digits as its factorization.

21824317 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 28.

The square root of 21824317 is about 4671.6503507861. The cubic root of 21824317 is about 279.4560741601.

The spelling of 21824317 in words is "twenty-one million, eight hundred twenty-four thousand, three hundred seventeen".