823457861 has 2 divisors, whose sum is σ = 823457862. Its totient is φ = 823457860.

The previous prime is 823457851. The next prime is 823457863. The reversal of 823457861 is 168754328.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 823345636 + 112225 = 28694^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 823457861 - 2¹⁸ = 823195717 is a prime.

It is a Sophie Germain prime.

Together with 823457863, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (823457863) 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, 411728930 + 411728931.

It is an arithmetic number, because the mean of its divisors is an integer number (411728931).

Almost surely, 2^823457861 is an apocalyptic number.

It is an amenable number.

823457861 is a deficient number, since it is larger than the sum of its proper divisors (1).

823457861 is an equidigital number, since it uses as much as digits as its factorization.

823457861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 322560, while the sum is 44.

The square root of 823457861 is about 28695.9554815657. The cubic root of 823457861 is about 937.3039774104.

The spelling of 823457861 in words is "eight hundred twenty-three million, four hundred fifty-seven thousand, eight hundred sixty-one".