829721 has 2 divisors, whose sum is σ = 829722. Its totient is φ = 829720.

The previous prime is 829709. The next prime is 829723. The reversal of 829721 is 127928.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 697225 + 132496 = 835^2 + 364^2 .

It is a cyclic number.

It is not a de Polignac number, because 829721 - 2⁶ = 829657 is a prime.

It is a Sophie Germain prime.

Together with 829723, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (829723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 414860 + 414861.

It is an arithmetic number, because the mean of its divisors is an integer number (414861).

2⁸²⁹⁷²¹ is an apocalyptic number.

It is an amenable number.

829721 is a deficient number, since it is larger than the sum of its proper divisors (1).

829721 is an equidigital number, since it uses as much as digits as its factorization.

829721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 29.

The square root of 829721 is about 910.8902239019. The cubic root of 829721 is about 93.9674325084.

The spelling of 829721 in words is "eight hundred twenty-nine thousand, seven hundred twenty-one".