816191 has 2 divisors, whose sum is σ = 816192. Its totient is φ = 816190.

The previous prime is 816169. The next prime is 816203. The reversal of 816191 is 191618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 816191 - 2¹⁴ = 799807 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 816191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (816121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408095 + 408096.

It is an arithmetic number, because the mean of its divisors is an integer number (408096).

2⁸¹⁶¹⁹¹ is an apocalyptic number.

816191 is a deficient number, since it is larger than the sum of its proper divisors (1).

816191 is an equidigital number, since it uses as much as digits as its factorization.

816191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 432, while the sum is 26.

The square root of 816191 is about 903.4328973421. The cubic root of 816191 is about 93.4538649688.

The spelling of 816191 in words is "eight hundred sixteen thousand, one hundred ninety-one".