99991899 has 36 divisors (see below), whose sum is σ = 171953496. Its totient is φ = 55798848.

The previous prime is 99991897. The next prime is 99991901. The reversal of 99991899 is 99819999.

It is an interprime number because it is at equal distance from previous prime (99991897) and next prime (99991901).

It is not a de Polignac number, because 99991899 - 2¹ = 99991897 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (99991891) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 16327 + ... + 21599.

It is an arithmetic number, because the mean of its divisors is an integer number (4776486).

Almost surely, 2^99991899 is an apocalyptic number.

99991899 is a deficient number, since it is larger than the sum of its proper divisors (71961597).

99991899 is a wasteful number, since it uses less digits than its factorization.

99991899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5336 (or 5326 counting only the distinct ones).

The product of its digits is 4251528, while the sum is 63.

The square root of 99991899 is about 9999.5949417964. The cubic root of 99991899 is about 464.1463491858.

The spelling of 99991899 in words is "ninety-nine million, nine hundred ninety-one thousand, eight hundred ninety-nine".