675721 has 4 divisors (see below), whose sum is σ = 692244. Its totient is φ = 659200.

The previous prime is 675713. The next prime is 675739. The reversal of 675721 is 127576.

675721 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 129600 + 546121 = 360^2 + 739^2 .

It is a cyclic number.

It is not a de Polignac number, because 675721 - 2³ = 675713 is a prime.

It is an Ulam number.

It is a nialpdrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 675721.

It is not an unprimeable number, because it can be changed into a prime (675751) 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, 8200 + ... + 8281.

It is an arithmetic number, because the mean of its divisors is an integer number (173061).

2⁶⁷⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

675721 is a deficient number, since it is larger than the sum of its proper divisors (16523).

675721 is a wasteful number, since it uses less digits than its factorization.

675721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16522.

The product of its digits is 2940, while the sum is 28.

The square root of 675721 is about 822.0225057746. The cubic root of 675721 is about 87.7517538739.

The spelling of 675721 in words is "six hundred seventy-five thousand, seven hundred twenty-one".