9993821 has 2 divisors, whose sum is σ = 9993822. Its totient is φ = 9993820.

The previous prime is 9993803. The next prime is 9993827. The reversal of 9993821 is 1283999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9369721 + 624100 = 3061^2 + 790^2 .

It is a cyclic number.

It is not a de Polignac number, because 9993821 - 2¹⁰ = 9992797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9993827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4996910 + 4996911.

It is an arithmetic number, because the mean of its divisors is an integer number (4996911).

Almost surely, 2^9993821 is an apocalyptic number.

It is an amenable number.

9993821 is a deficient number, since it is larger than the sum of its proper divisors (1).

9993821 is an equidigital number, since it uses as much as digits as its factorization.

9993821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 41.

The square root of 9993821 is about 3161.3005235188. The cubic root of 9993821 is about 215.3990856873.

The spelling of 9993821 in words is "nine million, nine hundred ninety-three thousand, eight hundred twenty-one".