1183991 has 4 divisors (see below), whose sum is σ = 1191984. Its totient is φ = 1176000.

The previous prime is 1183981. The next prime is 1183993. The reversal of 1183991 is 1993811.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1183991 - 2¹⁰ = 1182967 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 (1183993) 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, 3770 + ... + 4071.

It is an arithmetic number, because the mean of its divisors is an integer number (297996).

2^1183991 is an apocalyptic number.

1183991 is a deficient number, since it is larger than the sum of its proper divisors (7993).

1183991 is an equidigital number, since it uses as much as digits as its factorization.

1183991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7992.

The product of its digits is 1944, while the sum is 32.

The square root of 1183991 is about 1088.1135051087. The cubic root of 1183991 is about 105.7911814005.

The spelling of 1183991 in words is "one million, one hundred eighty-three thousand, nine hundred ninety-one".