99891191 has 2 divisors, whose sum is σ = 99891192. Its totient is φ = 99891190.

The previous prime is 99891163. The next prime is 99891251. The reversal of 99891191 is 19119899.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 99891191 - 2²⁶ = 32782327 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99891791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49945595 + 49945596.

It is an arithmetic number, because the mean of its divisors is an integer number (49945596).

Almost surely, 2^99891191 is an apocalyptic number.

99891191 is a deficient number, since it is larger than the sum of its proper divisors (1).

99891191 is an equidigital number, since it uses as much as digits as its factorization.

99891191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 52488, while the sum is 47.

The square root of 99891191 is about 9994.5580692695. The cubic root of 99891191 is about 463.9904733850.

The spelling of 99891191 in words is "ninety-nine million, eight hundred ninety-one thousand, one hundred ninety-one".