288721 has 4 divisors (see below), whose sum is σ = 294912. Its totient is φ = 282532.

The previous prime is 288697. The next prime is 288731. The reversal of 288721 is 127882.

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 a cyclic number.

It is not a de Polignac number, because 288721 - 2⁵ = 288689 is a prime.

It is a Duffinian number.

288721 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 288721.

It is not an unprimeable number, because it can be changed into a prime (288731) 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, 3025 + ... + 3118.

It is an arithmetic number, because the mean of its divisors is an integer number (73728).

2²⁸⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

288721 is a deficient number, since it is larger than the sum of its proper divisors (6191).

288721 is an equidigital number, since it uses as much as digits as its factorization.

288721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6190.

The product of its digits is 1792, while the sum is 28.

The square root of 288721 is about 537.3276467855. The cubic root of 288721 is about 66.0936076085.

The spelling of 288721 in words is "two hundred eighty-eight thousand, seven hundred twenty-one".