99991908 has 120 divisors (see below), whose sum is σ = 283236800. Its totient is φ = 30652992.

The previous prime is 99991901. The next prime is 99991933. The reversal of 99991908 is 80919999.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (99991901) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 227553 + ... + 227991.

Almost surely, 2^99991908 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99991908, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (141618400).

99991908 is an abundant number, since it is smaller than the sum of its proper divisors (183244892).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

99991908 is a wasteful number, since it uses less digits than its factorization.

99991908 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 472392, while the sum is 54.

The square root of 99991908 is about 9999.5953918146. The cubic root of 99991908 is about 464.1463631113.

The spelling of 99991908 in words is "ninety-nine million, nine hundred ninety-one thousand, nine hundred eight".