705721 has 4 divisors (see below), whose sum is σ = 747252. Its totient is φ = 664192.

The previous prime is 705713. The next prime is 705737. The reversal of 705721 is 127507.

705721 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.

It can be written as a sum of positive squares in 2 ways, for example, as 541696 + 164025 = 736^2 + 405^2 .

It is a cyclic number.

It is not a de Polignac number, because 705721 - 2³ = 705713 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 705692 and 705701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (705751) 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, 20740 + ... + 20773.

It is an arithmetic number, because the mean of its divisors is an integer number (186813).

2⁷⁰⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

705721 is a deficient number, since it is larger than the sum of its proper divisors (41531).

705721 is a wasteful number, since it uses less digits than its factorization.

705721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41530.

The product of its (nonzero) digits is 490, while the sum is 22.

The square root of 705721 is about 840.0720207220. The cubic root of 705721 is about 89.0316345903.

The spelling of 705721 in words is "seven hundred five thousand, seven hundred twenty-one".