812191 has 2 divisors, whose sum is σ = 812192. Its totient is φ = 812190.

The previous prime is 812183. The next prime is 812213. The reversal of 812191 is 191218.

It is an a-pointer prime, because the next prime (812213) can be obtained adding 812191 to its sum of digits (22).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 812191 - 2³ = 812183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (812101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406095 + 406096.

It is an arithmetic number, because the mean of its divisors is an integer number (406096).

2⁸¹²¹⁹¹ is an apocalyptic number.

812191 is a deficient number, since it is larger than the sum of its proper divisors (1).

812191 is an equidigital number, since it uses as much as digits as its factorization.

812191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 22.

The square root of 812191 is about 901.2164002059. The cubic root of 812191 is about 93.3009482313.

The spelling of 812191 in words is "eight hundred twelve thousand, one hundred ninety-one".