1991167 has 4 divisors (see below), whose sum is σ = 2000320. Its totient is φ = 1982016.

The previous prime is 1991153. The next prime is 1991177. The reversal of 1991167 is 7611991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7611991 = 227 ⋅33533.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1991167 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991107) 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, 4242 + ... + 4687.

It is an arithmetic number, because the mean of its divisors is an integer number (500080).

2^1991167 is an apocalyptic number.

1991167 is a deficient number, since it is larger than the sum of its proper divisors (9153).

1991167 is an equidigital number, since it uses as much as digits as its factorization.

1991167 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9152.

The product of its digits is 3402, while the sum is 34.

The square root of 1991167 is about 1411.0871695257. The cubic root of 1991167 is about 125.8063498808.

The spelling of 1991167 in words is "one million, nine hundred ninety-one thousand, one hundred sixty-seven".