709721 has 4 divisors (see below), whose sum is σ = 711732. Its totient is φ = 707712.

The previous prime is 709703. The next prime is 709729. The reversal of 709721 is 127907.

709721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 127907 = 13 ⋅9839.

It can be written as a sum of positive squares in 2 ways, for example, as 336400 + 373321 = 580^2 + 611^2 .

It is a cyclic number.

It is not a de Polignac number, because 709721 - 2¹⁴ = 693337 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 709721.

It is not an unprimeable number, because it can be changed into a prime (709729) 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, 320 + ... + 1233.

It is an arithmetic number, because the mean of its divisors is an integer number (177933).

2⁷⁰⁹⁷²¹ is an apocalyptic number.

It is an amenable number.

709721 is a deficient number, since it is larger than the sum of its proper divisors (2011).

709721 is a wasteful number, since it uses less digits than its factorization.

709721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2010.

The product of its (nonzero) digits is 882, while the sum is 26.

The square root of 709721 is about 842.4494050090. The cubic root of 709721 is about 89.1995271011.

The spelling of 709721 in words is "seven hundred nine thousand, seven hundred twenty-one".