440821 has 2 divisors, whose sum is σ = 440822. Its totient is φ = 440820.

The previous prime is 440809. The next prime is 440831. The reversal of 440821 is 128044.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 342225 + 98596 = 585^2 + 314^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-440821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (440831) 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 as a sum of consecutive naturals, namely, 220410 + 220411.

It is an arithmetic number, because the mean of its divisors is an integer number (220411).

2⁴⁴⁰⁸²¹ is an apocalyptic number.

It is an amenable number.

440821 is a deficient number, since it is larger than the sum of its proper divisors (1).

440821 is an equidigital number, since it uses as much as digits as its factorization.

440821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 440821 is about 663.9435216944. The cubic root of 440821 is about 76.1063262463.

Adding to 440821 its reverse (128044), we get a palindrome (568865).

The spelling of 440821 in words is "four hundred forty thousand, eight hundred twenty-one".