825721 has 8 divisors (see below), whose sum is σ = 936320. Its totient is φ = 721872.

The previous prime is 825709. The next prime is 825733. The reversal of 825721 is 127528.

It is an interprime number because it is at equal distance from previous prime (825709) and next prime (825733).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 825721 - 2⁵ = 825689 is a prime.

It is a d-powerful number, because it can be written as 8³ + 2⁴ + 7⁷ + 5⁴ + 2¹⁰ + 1 .

825721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (825701) 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 in 7 ways as a sum of consecutive naturals, for example, 1425 + ... + 1918.

It is an arithmetic number, because the mean of its divisors is an integer number (117040).

2⁸²⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

825721 is a deficient number, since it is larger than the sum of its proper divisors (110599).

825721 is a wasteful number, since it uses less digits than its factorization.

825721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3375.

The product of its digits is 1120, while the sum is 25.

The square root of 825721 is about 908.6919169884. The cubic root of 825721 is about 93.8161867432.

The spelling of 825721 in words is "eight hundred twenty-five thousand, seven hundred twenty-one".