843721 has 4 divisors (see below), whose sum is σ = 848772. Its totient is φ = 838672.

The previous prime is 843701. The next prime is 843737. The reversal of 843721 is 127348.

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 525625 + 318096 = 725^2 + 564^2 .

It is a cyclic number.

It is not a de Polignac number, because 843721 - 2⁹ = 843209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (843701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2266 + ... + 2611.

It is an arithmetic number, because the mean of its divisors is an integer number (212193).

2⁸⁴³⁷²¹ is an apocalyptic number.

It is an amenable number.

843721 is a deficient number, since it is larger than the sum of its proper divisors (5051).

843721 is a wasteful number, since it uses less digits than its factorization.

843721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5050.

The product of its digits is 1344, while the sum is 25.

The square root of 843721 is about 918.5428678075. The cubic root of 843721 is about 94.4929961309.

The spelling of 843721 in words is "eight hundred forty-three thousand, seven hundred twenty-one".