1991734768200 has 384 divisors, whose sum is σ = 6372151441920. Its totient is φ = 514459545600.

The previous prime is 1991734768187. The next prime is 1991734768201. The reversal of 1991734768200 is 28674371991.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1991734768201) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 595078927 + ... + 595082273.

It is an arithmetic number, because the mean of its divisors is an integer number (16594144380).

Almost surely, 2^{1991734768200} is an apocalyptic number.

1991734768200 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 1991734768200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3186075720960).

1991734768200 is an abundant number, since it is smaller than the sum of its proper divisors (4380416673720).

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

1991734768200 is a wasteful number, since it uses less digits than its factorization.

1991734768200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3677 (or 3668 counting only the distinct ones).

The product of its (nonzero) digits is 4572288, while the sum is 57.

The spelling of 1991734768200 in words is "one trillion, nine hundred ninety-one billion, seven hundred thirty-four million, seven hundred sixty-eight thousand, two hundred".