99909991000 has 32 divisors (see below), whose sum is σ = 233789381280. Its totient is φ = 39963996000.

The previous prime is 99909990989. The next prime is 99909991007. The reversal of 99909991000 is 19990999.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99909991007) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49953996 + ... + 49955995.

It is an arithmetic number, because the mean of its divisors is an integer number (7305918165).

Almost surely, 2^99909991000 is an apocalyptic number.

It is an amenable number.

99909991000 is an abundant number, since it is smaller than the sum of its proper divisors (133879390280).

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

99909991000 is a wasteful number, since it uses less digits than its factorization.

99909991000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 99910012 (or 99909998 counting only the distinct ones).

The product of its (nonzero) digits is 531441, while the sum is 55.

It can be divided in two parts, 9990999 and 1000, that added together give a palindrome (9991999).

The spelling of 99909991000 in words is "ninety-nine billion, nine hundred nine million, nine hundred ninety-one thousand".