99903821 has 2 divisors, whose sum is σ = 99903822. Its totient is φ = 99903820.

The previous prime is 99903809. The next prime is 99903823. The reversal of 99903821 is 12830999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96255721 + 3648100 = 9811^2 + 1910^2 .

It is an emirp because it is prime and its reverse (12830999) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99903821 is a prime.

Together with 99903823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99903823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49951910 + 49951911.

It is an arithmetic number, because the mean of its divisors is an integer number (49951911).

Almost surely, 2^99903821 is an apocalyptic number.

It is an amenable number.

99903821 is a deficient number, since it is larger than the sum of its proper divisors (1).

99903821 is an equidigital number, since it uses as much as digits as its factorization.

99903821 is an odious number, because the sum of its binary digits is odd.

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

The square root of 99903821 is about 9995.1898931436. The cubic root of 99903821 is about 464.0100278377.

The spelling of 99903821 in words is "ninety-nine million, nine hundred three thousand, eight hundred twenty-one".