8286721 has 4 divisors (see below), whose sum is σ = 8572500. Its totient is φ = 8000944.

The previous prime is 8286713. The next prime is 8286731. The reversal of 8286721 is 1276828.

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 1860496 + 6426225 = 1364^2 + 2535^2 .

It is a cyclic number.

It is not a de Polignac number, because 8286721 - 2³ = 8286713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8286731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142846 + ... + 142903.

It is an arithmetic number, because the mean of its divisors is an integer number (2143125).

Almost surely, 2^8286721 is an apocalyptic number.

It is an amenable number.

8286721 is a deficient number, since it is larger than the sum of its proper divisors (285779).

8286721 is a wasteful number, since it uses less digits than its factorization.

8286721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285778.

The product of its digits is 10752, while the sum is 34.

The square root of 8286721 is about 2878.6665315733. Note that the first 3 decimals coincide. The cubic root of 8286721 is about 202.3613520259.

The spelling of 8286721 in words is "eight million, two hundred eighty-six thousand, seven hundred twenty-one".