1000191 has 4 divisors (see below), whose sum is σ = 1333592. Its totient is φ = 666792.

The previous prime is 1000187. The next prime is 1000193. The reversal of 1000191 is 1910001.

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

It is not a de Polignac number, because 1000191 - 2² = 1000187 is a prime.

It is a D-number.

It is a Duffinian number.

1000191 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000193) 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, 166696 + ... + 166701.

It is an arithmetic number, because the mean of its divisors is an integer number (333398).

2^1000191 is an apocalyptic number.

1000191 is a deficient number, since it is larger than the sum of its proper divisors (333401).

1000191 is an equidigital number, since it uses as much as digits as its factorization.

1000191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333400.

The product of its (nonzero) digits is 9, while the sum is 12.

The square root of 1000191 is about 1000.0954954403. The cubic root of 1000191 is about 100.0063662614.

Adding to 1000191 its reverse (1910001), we get a palindrome (2910192).

The spelling of 1000191 in words is "one million, one hundred ninety-one", and thus it is an aban number.