999990000 has 300 divisors, whose sum is σ = 3595624032. Its totient is φ = 259200000.

The previous prime is 999989981. The next prime is 999990011. The reversal of 999990000 is 99999.

It is a tau number, because it is divible by the number of its divisors (300).

It is a Harshad number since it is a multiple of its sum of digits (45).

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 polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 3689865 + ... + 3690135.

Almost surely, 2^999990000 is an apocalyptic number.

999990000 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 999990000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1797812016).

999990000 is an abundant number, since it is smaller than the sum of its proper divisors (2595634032).

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

999990000 is a wasteful number, since it uses less digits than its factorization.

999990000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 346 (or 322 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 45.

The square root of 999990000 is about 31622.6184874055. The cubic root of 999990000 is about 999.9966666556.

Multiplying 999990000 by its reverse (99999), we get a square (99998000010000 = 9999900²).

999990000 divided by its reverse (99999) gives a 4-th power (10000 = 10⁴).

It can be divided in two parts, 9999 and 90000, that added together give a palindrome (99999).

The spelling of 999990000 in words is "nine hundred ninety-nine million, nine hundred ninety thousand".