605721 has 4 divisors (see below), whose sum is σ = 807632. Its totient is φ = 403812.

The previous prime is 605719. The next prime is 605779. The reversal of 605721 is 127506.

605721 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 a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 605721 - 2¹ = 605719 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (605021) 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, 100951 + ... + 100956.

It is an arithmetic number, because the mean of its divisors is an integer number (201908).

2⁶⁰⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

605721 is a deficient number, since it is larger than the sum of its proper divisors (201911).

605721 is a wasteful number, since it uses less digits than its factorization.

605721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201910.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 605721 is about 778.2807976560. The cubic root of 605721 is about 84.6104900114.

It can be divided in two parts, 605 and 721, that added together give a triangular number (1326 = T₅₁).

The spelling of 605721 in words is "six hundred five thousand, seven hundred twenty-one".