824316721 has 2 divisors, whose sum is σ = 824316722. Its totient is φ = 824316720.

The previous prime is 824316697. The next prime is 824316733. The reversal of 824316721 is 127613428.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 522808225 + 301508496 = 22865^2 + 17364^2 .

It is a cyclic number.

It is not a de Polignac number, because 824316721 - 2²⁵ = 790762289 is a prime.

It is not a weakly prime, because it can be changed into another prime (824316761) 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, 412158360 + 412158361.

It is an arithmetic number, because the mean of its divisors is an integer number (412158361).

Almost surely, 2^824316721 is an apocalyptic number.

It is an amenable number.

824316721 is a deficient number, since it is larger than the sum of its proper divisors (1).

824316721 is an equidigital number, since it uses as much as digits as its factorization.

824316721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16128, while the sum is 34.

The square root of 824316721 is about 28710.9164082235. The cubic root of 824316721 is about 937.6297310485.

It can be divided in two parts, 8243 and 16721, that added together give a square (24964 = 158²).

The spelling of 824316721 in words is "eight hundred twenty-four million, three hundred sixteen thousand, seven hundred twenty-one".