991648 has 48 divisors (see below), whose sum is σ = 2358720. Its totient is φ = 400896.

The previous prime is 991643. The next prime is 991651. The reversal of 991648 is 846199.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991643) by changing a digit.

991648 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, 4140 + ... + 4372.

It is an arithmetic number, because the mean of its divisors is an integer number (49140).

2⁹⁹¹⁶⁴⁸ 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 991648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1179360).

991648 is an abundant number, since it is smaller than the sum of its proper divisors (1367072).

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

991648 is a wasteful number, since it uses less digits than its factorization.

991648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 269 (or 261 counting only the distinct ones).

The product of its digits is 15552, while the sum is 37.

The square root of 991648 is about 995.8152439082. The cubic root of 991648 is about 99.7208213179.

The spelling of 991648 in words is "nine hundred ninety-one thousand, six hundred forty-eight".