1991183040 has 896 divisors, whose sum is σ = 9094256640. Its totient is φ = 398131200.

The previous prime is 1991183003. The next prime is 1991183053. The reversal of 1991183040 is 403811991.

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

It is a junction number, because it is equal to n+sod(n) for n = 1991182986 and 1991183004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 27276444 + ... + 27276516.

It is an arithmetic number, because the mean of its divisors is an integer number (10149840).

Almost surely, 2^1991183040 is an apocalyptic number.

1991183040 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 1991183040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4547128320).

1991183040 is an abundant number, since it is smaller than the sum of its proper divisors (7103073600).

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

1991183040 is a wasteful number, since it uses less digits than its factorization.

1991183040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 1991183040 is about 44622.6740570307. The cubic root of 1991183040 is about 1258.0668769416.

The spelling of 1991183040 in words is "one billion, nine hundred ninety-one million, one hundred eighty-three thousand, forty".