991983263040 has 672 divisors, whose sum is σ = 4301816014080. Its totient is φ = 203806310400.

The previous prime is 991983263039. The next prime is 991983263077. The reversal of 991983263040 is 40362389199.

991983263040 is a `hidden beast` number, since 9 + 9 + 1 + 9 + 8 + 326 + 304 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 19711510 + ... + 19761770.

Almost surely, 2^991983263040 is an apocalyptic number.

991983263040 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 991983263040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2150908007040).

991983263040 is an abundant number, since it is smaller than the sum of its proper divisors (3309832751040).

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

991983263040 is a wasteful number, since it uses less digits than its factorization.

991983263040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50391 (or 50378 counting only the distinct ones).

The product of its (nonzero) digits is 2519424, while the sum is 54.

The spelling of 991983263040 in words is "nine hundred ninety-one billion, nine hundred eighty-three million, two hundred sixty-three thousand, forty".