99993821 has 2 divisors, whose sum is σ = 99993822. Its totient is φ = 99993820.

The previous prime is 99993799. The next prime is 99993833. The reversal of 99993821 is 12839999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 93818596 + 6175225 = 9686^2 + 2485^2 .

It is a cyclic number.

It is not a de Polignac number, because 99993821 - 2¹⁰ = 99992797 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99993821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99993841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49996910 + 49996911.

It is an arithmetic number, because the mean of its divisors is an integer number (49996911).

Almost surely, 2^99993821 is an apocalyptic number.

It is an amenable number.

99993821 is a deficient number, since it is larger than the sum of its proper divisors (1).

99993821 is an equidigital number, since it uses as much as digits as its factorization.

99993821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 314928, while the sum is 50.

The square root of 99993821 is about 9999.6910452273. The cubic root of 99993821 is about 464.1493230386.

The spelling of 99993821 in words is "ninety-nine million, nine hundred ninety-three thousand, eight hundred twenty-one".