991768 has 16 divisors (see below), whose sum is σ = 1874160. Its totient is φ = 492000.

The previous prime is 991751. The next prime is 991777. The reversal of 991768 is 867199.

991768 is nontrivially palindromic in base 7.

It is a plaindrome in base 15.

It is a self number, because there is not a number n which added to its sum of digits gives 991768.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 798 + ... + 1618.

It is an arithmetic number, because the mean of its divisors is an integer number (117135).

2⁹⁹¹⁷⁶⁸ is an apocalyptic number.

It is an amenable number.

991768 is a deficient number, since it is larger than the sum of its proper divisors (882392).

991768 is a wasteful number, since it uses less digits than its factorization.

991768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 978 (or 974 counting only the distinct ones).

The product of its digits is 27216, while the sum is 40.

The square root of 991768 is about 995.8754942261. The cubic root of 991768 is about 99.7248435839.

The spelling of 991768 in words is "nine hundred ninety-one thousand, seven hundred sixty-eight".