999000990 has 96 divisors (see below), whose sum is σ = 2893756320. Its totient is φ = 237420288.

The previous prime is 999000967. The next prime is 999000991. The reversal of 999000990 is 99000999.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (999000991) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19209 + ... + 48651.

It is an arithmetic number, because the mean of its divisors is an integer number (30143295).

Almost surely, 2^999000990 is an apocalyptic number.

999000990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 999000990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1446878160).

999000990 is an abundant number, since it is smaller than the sum of its proper divisors (1894755330).

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

999000990 is a wasteful number, since it uses less digits than its factorization.

999000990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29498 (or 29495 counting only the distinct ones).

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

The square root of 999000990 is about 31606.9769196613. The cubic root of 999000990 is about 999.6668857139. Note that the first 3 decimals are identical.

The spelling of 999000990 in words is "nine hundred ninety-nine million, nine hundred ninety", and thus it is an aban number.