830721 has 4 divisors (see below), whose sum is σ = 1107632. Its totient is φ = 553812.

The previous prime is 830719. The next prime is 830729. The reversal of 830721 is 127038.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 830721 - 2¹ = 830719 is a prime.

It is a D-number.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 830721.

It is not an unprimeable number, because it can be changed into a prime (830729) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 138451 + ... + 138456.

It is an arithmetic number, because the mean of its divisors is an integer number (276908).

2⁸³⁰⁷²¹ is an apocalyptic number.

It is an amenable number.

830721 is a deficient number, since it is larger than the sum of its proper divisors (276911).

830721 is a wasteful number, since it uses less digits than its factorization.

830721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 276910.

The product of its (nonzero) digits is 336, while the sum is 21.

The square root of 830721 is about 911.4389721753. The cubic root of 830721 is about 94.0051679670.

Adding to 830721 its reverse (127038), we get a palindrome (957759).

It can be divided in two parts, 830 and 721, that added together give a palindrome (1551).

The spelling of 830721 in words is "eight hundred thirty thousand, seven hundred twenty-one".