823421 has 2 divisors, whose sum is σ = 823422. Its totient is φ = 823420.

The previous prime is 823399. The next prime is 823447. The reversal of 823421 is 124328.

823421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 532900 + 290521 = 730^2 + 539^2 .

It is a cyclic number.

It is not a de Polignac number, because 823421 - 2⁶ = 823357 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 823393 and 823402.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411710 + 411711.

It is an arithmetic number, because the mean of its divisors is an integer number (411711).

2⁸²³⁴²¹ is an apocalyptic number.

It is an amenable number.

823421 is a deficient number, since it is larger than the sum of its proper divisors (1).

823421 is an equidigital number, since it uses as much as digits as its factorization.

823421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 384, while the sum is 20.

The square root of 823421 is about 907.4254790340. The cubic root of 823421 is about 93.7289991478.

Adding to 823421 its reverse (124328), we get a palindrome (947749).

The spelling of 823421 in words is "eight hundred twenty-three thousand, four hundred twenty-one".