999999900 has 108 divisors (see below), whose sum is σ = 3148236000. Its totient is φ = 265493760.

The previous prime is 999999893. The next prime is 999999929. The reversal of 999999900 is 9999999.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 212776 + ... + 217424.

Almost surely, 2^999999900 is an apocalyptic number.

999999900 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 999999900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1574118000).

999999900 is an abundant number, since it is smaller than the sum of its proper divisors (2148236100).

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

999999900 is a wasteful number, since it uses less digits than its factorization.

999999900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4908 (or 4898 counting only the distinct ones).

The product of its (nonzero) digits is 4782969, while the sum is 63.

The square root of 999999900 is about 31622.7750205449. The cubic root of 999999900 is about 999.9999666667. Note that the first 4 decimals are identical.

999999900 divided by its reverse (9999999) gives a square (100 = 10²).

It can be divided in two parts, 99 and 9999900, that added together give a palindrome (9999999).

The spelling of 999999900 in words is "nine hundred ninety-nine million, nine hundred ninety-nine thousand, nine hundred".