823238021 has 2 divisors, whose sum is σ = 823238022. Its totient is φ = 823238020.

The previous prime is 823237997. The next prime is 823238071. The reversal of 823238021 is 120832328.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 717436225 + 105801796 = 26785^2 + 10286^2 .

It is a cyclic number.

It is not a de Polignac number, because 823238021 - 2¹⁸ = 822975877 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823238071) 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, 411619010 + 411619011.

It is an arithmetic number, because the mean of its divisors is an integer number (411619011).

Almost surely, 2^823238021 is an apocalyptic number.

It is an amenable number.

823238021 is a deficient number, since it is larger than the sum of its proper divisors (1).

823238021 is an equidigital number, since it uses as much as digits as its factorization.

823238021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 29.

The square root of 823238021 is about 28692.1247209056. The cubic root of 823238021 is about 937.2205587536.

The spelling of 823238021 in words is "eight hundred twenty-three million, two hundred thirty-eight thousand, twenty-one".