9999823 has 2 divisors, whose sum is σ = 9999824. Its totient is φ = 9999822.

The previous prime is 9999761. The next prime is 9999863. The reversal of 9999823 is 3289999.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9999823 is a prime.

It is an Ulam number.

9999823 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9999863) 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, 4999911 + 4999912.

It is an arithmetic number, because the mean of its divisors is an integer number (4999912).

Almost surely, 2^9999823 is an apocalyptic number.

9999823 is a deficient number, since it is larger than the sum of its proper divisors (1).

9999823 is an equidigital number, since it uses as much as digits as its factorization.

9999823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 314928, while the sum is 49.

The square root of 9999823 is about 3162.2496738872. The cubic root of 9999823 is about 215.4421978792.

The spelling of 9999823 in words is "nine million, nine hundred ninety-nine thousand, eight hundred twenty-three".