99121989191 has 2 divisors, whose sum is σ = 99121989192. Its totient is φ = 99121989190.

The previous prime is 99121989179. The next prime is 99121989209. The reversal of 99121989191 is 19198912199.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99121989191 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99121989191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99121989121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49560994595 + 49560994596.

It is an arithmetic number, because the mean of its divisors is an integer number (49560994596).

Almost surely, 2^99121989191 is an apocalyptic number.

99121989191 is a deficient number, since it is larger than the sum of its proper divisors (1).

99121989191 is an equidigital number, since it uses as much as digits as its factorization.

99121989191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 944784, while the sum is 59.

The spelling of 99121989191 in words is "ninety-nine billion, one hundred twenty-one million, nine hundred eighty-nine thousand, one hundred ninety-one".