1991179 has 4 divisors (see below), whose sum is σ = 2077776. Its totient is φ = 1904584.

The previous prime is 1991177. The next prime is 1991189. The reversal of 1991179 is 9711991.

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

It is not a de Polignac number, because 1991179 - 2¹ = 1991177 is a prime.

It is a Duffinian number.

1991179 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1991177) 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, 43264 + ... + 43309.

It is an arithmetic number, because the mean of its divisors is an integer number (519444).

2^1991179 is an apocalyptic number.

1991179 is a deficient number, since it is larger than the sum of its proper divisors (86597).

1991179 is an equidigital number, since it uses as much as digits as its factorization.

1991179 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86596.

The product of its digits is 5103, while the sum is 37.

The square root of 1991179 is about 1411.0914215599. The cubic root of 1991179 is about 125.8066026092.

It can be divided in two parts, 199 and 1179, that added together give a triangular number (1378 = T₅₂).

The spelling of 1991179 in words is "one million, nine hundred ninety-one thousand, one hundred seventy-nine".