991392 has 48 divisors (see below), whose sum is σ = 2721600. Its totient is φ = 315392.

The previous prime is 991387. The next prime is 991409. The reversal of 991392 is 293199.

It is a tau number, because it is divible by the number of its divisors (48).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991392.

It is an unprimeable 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 7 ways as a sum of consecutive naturals, for example, 1984 + ... + 2432.

It is an arithmetic number, because the mean of its divisors is an integer number (56700).

2⁹⁹¹³⁹² is an apocalyptic number.

991392 is a gapful number since it is divisible by the number (92) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991392, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1360800).

991392 is an abundant number, since it is smaller than the sum of its proper divisors (1730208).

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

991392 is a wasteful number, since it uses less digits than its factorization.

991392 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 485 (or 477 counting only the distinct ones).

The product of its digits is 4374, while the sum is 33.

The square root of 991392 is about 995.6866977117. The cubic root of 991392 is about 99.7122393993.

The spelling of 991392 in words is "nine hundred ninety-one thousand, three hundred ninety-two".