1991175788448 has 768 divisors, whose sum is σ = 7315660800000. Its totient is φ = 511864012800.

The previous prime is 1991175788423. The next prime is 1991175788507. The reversal of 1991175788448 is 8448875711991.

1991175788448 is a `hidden beast` number, since 1 + 9 + 9 + 1 + 1 + 7 + 578 + 8 + 4 + 48 = 666.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4434689728 + ... + 4434690176.

It is an arithmetic number, because the mean of its divisors is an integer number (9525600000).

Almost surely, 2^{1991175788448} is an apocalyptic number.

1991175788448 is a gapful number since it is divisible by the number (18) 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 1991175788448, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3657830400000).

1991175788448 is an abundant number, since it is smaller than the sum of its proper divisors (5324485011552).

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

1991175788448 is a wasteful number, since it uses less digits than its factorization.

1991175788448 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1026 (or 1012 counting only the distinct ones).

The product of its digits is 162570240, while the sum is 72.

The spelling of 1991175788448 in words is "one trillion, nine hundred ninety-one billion, one hundred seventy-five million, seven hundred eighty-eight thousand, four hundred forty-eight".