99810121 has 2 divisors, whose sum is σ = 99810122. Its totient is φ = 99810120.

The previous prime is 99810047. The next prime is 99810131. The reversal of 99810121 is 12101899.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78057225 + 21752896 = 8835^2 + 4664^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99810121 is a prime.

It is not a weakly prime, because it can be changed into another prime (99810131) 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, 49905060 + 49905061.

It is an arithmetic number, because the mean of its divisors is an integer number (49905061).

Almost surely, 2^99810121 is an apocalyptic number.

It is an amenable number.

99810121 is a deficient number, since it is larger than the sum of its proper divisors (1).

99810121 is an equidigital number, since it uses as much as digits as its factorization.

99810121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 99810121 is about 9990.5015389619. The cubic root of 99810121 is about 463.8649171406.

The spelling of 99810121 in words is "ninety-nine million, eight hundred ten thousand, one hundred twenty-one".