991383 has 8 divisors (see below), whose sum is σ = 1327728. Its totient is φ = 657984.

The previous prime is 991381. The next prime is 991387. The reversal of 991383 is 383199.

991383 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 991383 - 2¹ = 991381 is a prime.

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

991383 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991383.

It is not an unprimeable number, because it can be changed into a prime (991381) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 235 + ... + 1427.

It is an arithmetic number, because the mean of its divisors is an integer number (165966).

2⁹⁹¹³⁸³ is an apocalyptic number.

991383 is a deficient number, since it is larger than the sum of its proper divisors (336345).

991383 is a wasteful number, since it uses less digits than its factorization.

991383 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1473.

The product of its digits is 5832, while the sum is 33.

The square root of 991383 is about 995.6821782075. The cubic root of 991383 is about 99.7119376644.

The spelling of 991383 in words is "nine hundred ninety-one thousand, three hundred eighty-three".