1991808000 has 1056 divisors, whose sum is σ = 9298947840. Its totient is φ = 398131200.

The previous prime is 1991807989. The next prime is 1991808023. The reversal of 1991808000 is 8081991.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 104831991 + ... + 104832009.

Almost surely, 2^1991808000 is an apocalyptic number.

1991808000 is a gapful number since it is divisible by the number (10) 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 1991808000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4649473920).

1991808000 is an abundant number, since it is smaller than the sum of its proper divisors (7307139840).

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

1991808000 is a wasteful number, since it uses less digits than its factorization.

1991808000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80 (or 49 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 1991808000 is about 44629.6762255789. The cubic root of 1991808000 is about 1258.1984836659.

Adding to 1991808000 its reverse (8081991), we get a palindrome (1999889991).

The spelling of 1991808000 in words is "one billion, nine hundred ninety-one million, eight hundred eight thousand".