991767168 has 192 divisors, whose sum is σ = 3433809600. Its totient is φ = 268406784.

The previous prime is 991767157. The next prime is 991767173. The reversal of 991767168 is 861767199.

It is a tau number, because it is divible by the number of its divisors (192).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 149980 + ... + 156452.

It is an arithmetic number, because the mean of its divisors is an integer number (17884425).

Almost surely, 2^991767168 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 991767168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1716904800).

991767168 is an abundant number, since it is smaller than the sum of its proper divisors (2442042432).

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

991767168 is a wasteful number, since it uses less digits than its factorization.

With its successor (991767169) it forms a Ruth-Aaron pair, since the sum of their prime factors is the same (6519).

991767168 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6519 (or 6504 counting only the distinct ones).

The product of its digits is 1143072, while the sum is 54.

The square root of 991767168 is about 31492.3350674414. The cubic root of 991767168 is about 997.2481569729.

The spelling of 991767168 in words is "nine hundred ninety-one million, seven hundred sixty-seven thousand, one hundred sixty-eight".