288821 has 6 divisors (see below), whose sum is σ = 312930. Its totient is φ = 266448.

The previous prime is 288817. The next prime is 288823. The reversal of 288821 is 128882.

It can be written as a sum of positive squares in 3 ways, for example, as 7921 + 280900 = 89^2 + 530^2 .

It is not a de Polignac number, because 288821 - 2² = 288817 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (288823) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 686 + ... + 1023.

It is an arithmetic number, because the mean of its divisors is an integer number (52155).

2²⁸⁸⁸²¹ is an apocalyptic number.

It is an amenable number.

288821 is a deficient number, since it is larger than the sum of its proper divisors (24109).

288821 is a wasteful number, since it uses less digits than its factorization.

288821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1735 (or 1722 counting only the distinct ones).

The product of its digits is 2048, while the sum is 29.

The square root of 288821 is about 537.4206918235. The cubic root of 288821 is about 66.1012373477.

The spelling of 288821 in words is "two hundred eighty-eight thousand, eight hundred twenty-one".