991200 has 144 divisors (see below), whose sum is σ = 3749760. Its totient is φ = 222720.

The previous prime is 991187. The next prime is 991201. The reversal of 991200 is 2199.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991201) by changing a digit.

991200 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 23 ways as a sum of consecutive naturals, for example, 16771 + ... + 16829.

It is an arithmetic number, because the mean of its divisors is an integer number (26040).

2⁹⁹¹²⁰⁰ 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 991200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1874880).

991200 is an abundant number, since it is smaller than the sum of its proper divisors (2758560).

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

991200 is a wasteful number, since it uses less digits than its factorization.

991200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89 (or 76 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 991200 is about 995.5902771723. The cubic root of 991200 is about 99.7058019908.

Adding to 991200 its reverse (2199), we get a palindrome (993399).

The spelling of 991200 in words is "nine hundred ninety-one thousand, two hundred".