991718 has 16 divisors (see below), whose sum is σ = 1831200. Its totient is φ = 392256.

The previous prime is 991717. The next prime is 991723. The reversal of 991718 is 817199.

It is a Smith number, since the sum of its digits (35) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991717) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2543 + ... + 2906.

It is an arithmetic number, because the mean of its divisors is an integer number (114450).

2⁹⁹¹⁷¹⁸ is an apocalyptic number.

991718 is a deficient number, since it is larger than the sum of its proper divisors (839482).

991718 is a wasteful number, since it uses less digits than its factorization.

991718 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5471.

The product of its digits is 4536, while the sum is 35.

The square root of 991718 is about 995.8503903700. The cubic root of 991718 is about 99.7231676792.

The spelling of 991718 in words is "nine hundred ninety-one thousand, seven hundred eighteen".