1991382055760 has 80 divisors (see below), whose sum is σ = 4666134384000. Its totient is φ = 790341539328.

The previous prime is 1991382055711. The next prime is 1991382055781. The reversal of 1991382055760 is 675502831991.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 1991382055696 and 1991382055705.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10863587 + ... + 11045373.

It is an arithmetic number, because the mean of its divisors is an integer number (58326679800).

Almost surely, 2^{1991382055760} is an apocalyptic number.

1991382055760 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 1991382055760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2333067192000).

1991382055760 is an abundant number, since it is smaller than the sum of its proper divisors (2674752328240).

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

1991382055760 is a wasteful number, since it uses less digits than its factorization.

1991382055760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182868 (or 182862 counting only the distinct ones).

The product of its (nonzero) digits is 4082400, while the sum is 56.

The spelling of 1991382055760 in words is "one trillion, nine hundred ninety-one billion, three hundred eighty-two million, fifty-five thousand, seven hundred sixty".