1991965774848 has 528 divisors, whose sum is σ = 6568822344960. Its totient is φ = 533249654784.

The previous prime is 1991965774837. The next prime is 1991965774889. The reversal of 1991965774848 is 8484775691991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 611593636 + ... + 611596892.

Almost surely, 2^{1991965774848} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991965774848, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3284411172480).

1991965774848 is an abundant number, since it is smaller than the sum of its proper divisors (4576856570112).

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

1991965774848 is a wasteful number, since it uses less digits than its factorization.

1991965774848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3550 (or 3525 counting only the distinct ones).

The product of its digits is 1097349120, while the sum is 78.

The spelling of 1991965774848 in words is "one trillion, nine hundred ninety-one billion, nine hundred sixty-five million, seven hundred seventy-four thousand, eight hundred forty-eight".