729821 has 2 divisors, whose sum is σ = 729822. Its totient is φ = 729820.

The previous prime is 729791. The next prime is 729851. The reversal of 729821 is 128927.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (729791) and next prime (729851).

It can be written as a sum of positive squares in only one way, i.e., 648025 + 81796 = 805^2 + 286^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-729821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (729851) 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, 364910 + 364911.

It is an arithmetic number, because the mean of its divisors is an integer number (364911).

2⁷²⁹⁸²¹ is an apocalyptic number.

It is an amenable number.

729821 is a deficient number, since it is larger than the sum of its proper divisors (1).

729821 is an equidigital number, since it uses as much as digits as its factorization.

729821 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 729821 is about 854.2956162828. The cubic root of 729821 is about 90.0337733329.

The spelling of 729821 in words is "seven hundred twenty-nine thousand, eight hundred twenty-one".