823751384921 has 2 divisors, whose sum is σ = 823751384922. Its totient is φ = 823751384920.

The previous prime is 823751384909. The next prime is 823751384947. The reversal of 823751384921 is 129483157328.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 504577232896 + 319174152025 = 710336^2 + 564955^2 .

It is a cyclic number.

It is not a de Polignac number, because 823751384921 - 2⁶ = 823751384857 is a prime.

It is not a weakly prime, because it can be changed into another prime (823751384221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411875692460 + 411875692461.

It is an arithmetic number, because the mean of its divisors is an integer number (411875692461).

Almost surely, 2^823751384921 is an apocalyptic number.

It is an amenable number.

823751384921 is a deficient number, since it is larger than the sum of its proper divisors (1).

823751384921 is an equidigital number, since it uses as much as digits as its factorization.

823751384921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2903040, while the sum is 53.

The spelling of 823751384921 in words is "eight hundred twenty-three billion, seven hundred fifty-one million, three hundred eighty-four thousand, nine hundred twenty-one".