1991382055759 has 8 divisors (see below), whose sum is σ = 2108534652000. Its totient is φ = 1874230845696.

The previous prime is 1991382055711. The next prime is 1991382055781. The reversal of 1991382055759 is 9575502831991.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1991382055759 - 2¹⁷ = 1991381924687 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1991382055759.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991382056759) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4767822 + ... + 5168644.

It is an arithmetic number, because the mean of its divisors is an integer number (263566831500).

Almost surely, 2^{1991382055759} is an apocalyptic number.

1991382055759 is a deficient number, since it is larger than the sum of its proper divisors (117152596241).

1991382055759 is a wasteful number, since it uses less digits than its factorization.

1991382055759 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693089.

The product of its (nonzero) digits is 30618000, while the sum is 64.

The spelling of 1991382055759 in words is "one trillion, nine hundred ninety-one billion, three hundred eighty-two million, fifty-five thousand, seven hundred fifty-nine".