1191991329990 has 96 divisors (see below), whose sum is σ = 3211744180320. Its totient is φ = 306358015488.

The previous prime is 1191991329989. The next prime is 1191991330007. The reversal of 1191991329990 is 999231991911.

1191991329990 is a `hidden beast` number, since 119 + 199 + 1 + 329 + 9 + 9 + 0 = 666.

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, 1063834 + ... + 1875026.

It is an arithmetic number, because the mean of its divisors is an integer number (33455668545).

Almost surely, 2^{1191991329990} is an apocalyptic number.

1191991329990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1191991329990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1605872090160).

1191991329990 is an abundant number, since it is smaller than the sum of its proper divisors (2019752850330).

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

1191991329990 is a wasteful number, since it uses less digits than its factorization.

1191991329990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 811798 (or 811795 counting only the distinct ones).

The product of its (nonzero) digits is 3188646, while the sum is 63.

The spelling of 1191991329990 in words is "one trillion, one hundred ninety-one billion, nine hundred ninety-one million, three hundred twenty-nine thousand, nine hundred ninety".