491688 has 24 divisors (see below), whose sum is σ = 1331850. Its totient is φ = 163872.

The previous prime is 491677. The next prime is 491707. The reversal of 491688 is 886194.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 412164 + 79524 = 642^2 + 282^2 .

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (36).

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

It is an unprimeable number.

491688 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3343 + ... + 3486.

491688 is a Friedman number, since it can be written as 81948*6, using all its digits and the basic arithmetic operations.

2⁴⁹¹⁶⁸⁸ is an apocalyptic number.

It is an amenable number.

491688 is an abundant number, since it is smaller than the sum of its proper divisors (840162).

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

491688 is a wasteful number, since it uses less digits than its factorization.

491688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6841 (or 6834 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 491688 is about 701.2046776798. The cubic root of 491688 is about 78.9277767525.

The spelling of 491688 in words is "four hundred ninety-one thousand, six hundred eighty-eight".