9921823 has 2 divisors, whose sum is σ = 9921824. Its totient is φ = 9921822.

The previous prime is 9921817. The next prime is 9921827. The reversal of 9921823 is 3281299.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 9921823 - 2⁹ = 9921311 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9921827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4960911 + 4960912.

It is an arithmetic number, because the mean of its divisors is an integer number (4960912).

Almost surely, 2^9921823 is an apocalyptic number.

9921823 is a deficient number, since it is larger than the sum of its proper divisors (1).

9921823 is an equidigital number, since it uses as much as digits as its factorization.

9921823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 34.

The square root of 9921823 is about 3149.8925378495. The cubic root of 9921823 is about 214.8805754647.

The spelling of 9921823 in words is "nine million, nine hundred twenty-one thousand, eight hundred twenty-three".