828721 has 2 divisors, whose sum is σ = 828722. Its totient is φ = 828720.

The previous prime is 828703. The next prime is 828731. The reversal of 828721 is 127828.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 583696 + 245025 = 764^2 + 495^2 .

It is a cyclic number.

It is not a de Polignac number, because 828721 - 2⁹ = 828209 is a prime.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 828721.

It is not a weakly prime, because it can be changed into another prime (828701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 414360 + 414361.

It is an arithmetic number, because the mean of its divisors is an integer number (414361).

2⁸²⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

828721 is a deficient number, since it is larger than the sum of its proper divisors (1).

828721 is an equidigital number, since it uses as much as digits as its factorization.

828721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 28.

The square root of 828721 is about 910.3411448463. The cubic root of 828721 is about 93.9296667179.

The spelling of 828721 in words is "eight hundred twenty-eight thousand, seven hundred twenty-one".