991103 has 4 divisors (see below), whose sum is σ = 1003128. Its totient is φ = 979080.

The previous prime is 991091. The next prime is 991127. The reversal of 991103 is 301199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 301199 = 53 ⋅5683.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5888 + ... + 6053.

It is an arithmetic number, because the mean of its divisors is an integer number (250782).

2⁹⁹¹¹⁰³ is an apocalyptic number.

991103 is a deficient number, since it is larger than the sum of its proper divisors (12025).

991103 is a wasteful number, since it uses less digits than its factorization.

991103 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12024.

The product of its (nonzero) digits is 243, while the sum is 23.

The square root of 991103 is about 995.5415611616. The cubic root of 991103 is about 99.7025494422.

The spelling of 991103 in words is "nine hundred ninety-one thousand, one hundred three".