991536 has 80 divisors (see below), whose sum is σ = 3166464. Its totient is φ = 260352.

The previous prime is 991531. The next prime is 991541. The reversal of 991536 is 635199.

It is an interprime number because it is at equal distance from previous prime (991531) and next prime (991541).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 991497 and 991506.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991536.

It is not an unprimeable number, because it can be changed into a prime (991531) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4255 + ... + 4481.

2⁹⁹¹⁵³⁶ 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 991536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1583232).

991536 is an abundant number, since it is smaller than the sum of its proper divisors (2174928).

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

991536 is a wasteful number, since it uses less digits than its factorization.

991536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 258 (or 252 counting only the distinct ones).

The product of its digits is 7290, while the sum is 33.

The square root of 991536 is about 995.7590069891. The cubic root of 991536 is about 99.7170669103.

The spelling of 991536 in words is "nine hundred ninety-one thousand, five hundred thirty-six".