991656 has 32 divisors (see below), whose sum is σ = 2755200. Its totient is φ = 330480.

The previous prime is 991651. The next prime is 991663. The reversal of 991656 is 656199.

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

It is a self number, because there is not a number n which added to its sum of digits gives 991656.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991656.

It is not an unprimeable number, because it can be changed into a prime (991651) by changing a digit.

991656 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2080 + ... + 2511.

It is an arithmetic number, because the mean of its divisors is an integer number (86100).

2⁹⁹¹⁶⁵⁶ is an apocalyptic number.

It is an amenable number.

991656 is an abundant number, since it is smaller than the sum of its proper divisors (1763544).

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

991656 is a wasteful number, since it uses less digits than its factorization.

991656 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4606 (or 4596 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 991656 is about 995.8192607095. The cubic root of 991656 is about 99.7210894791.

The spelling of 991656 in words is "nine hundred ninety-one thousand, six hundred fifty-six".