99999999900 has 180 divisors, whose sum is σ = 332922585688. Its totient is φ = 25945868160.

The previous prime is 99999999871. The next prime is 99999999907. The reversal of 99999999900 is 999999999.

It is a tau number, because it is divible by the number of its divisors (180).

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 99999999900.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999999907) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 132867 + ... + 466533.

Almost surely, 2^99999999900 is an apocalyptic number.

99999999900 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99999999900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (166461292844).

99999999900 is an abundant number, since it is smaller than the sum of its proper divisors (232922585788).

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

99999999900 is a wasteful number, since it uses less digits than its factorization.

99999999900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333730 (or 333714 counting only the distinct ones).

The product of its (nonzero) digits is 387420489, while the sum is 81.

99999999900 divided by its reverse (999999999) gives a square (100 = 10²).

It can be divided in two parts, 99 and 999999900, that added together give a palindrome (999999999).

The spelling of 99999999900 in words is "ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred".