823981 has 2 divisors, whose sum is σ = 823982. Its totient is φ = 823980.

The previous prime is 823969. The next prime is 823993. The reversal of 823981 is 189328.

823981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (823969) and next prime (823993).

It can be written as a sum of positive squares in only one way, i.e., 756900 + 67081 = 870^2 + 259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-823981 is a prime.

It is a super-2 number, since 2×823981² = 1357889376722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411990 + 411991.

It is an arithmetic number, because the mean of its divisors is an integer number (411991).

2⁸²³⁹⁸¹ is an apocalyptic number.

It is an amenable number.

823981 is a deficient number, since it is larger than the sum of its proper divisors (1).

823981 is an equidigital number, since it uses as much as digits as its factorization.

823981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 31.

The square root of 823981 is about 907.7339918721. The cubic root of 823981 is about 93.7502423697.

The spelling of 823981 in words is "eight hundred twenty-three thousand, nine hundred eighty-one".