78191 has 2 divisors, whose sum is σ = 78192. Its totient is φ = 78190.

The previous prime is 78179. The next prime is 78193. The reversal of 78191 is 19187.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78191 - 2¹⁰ = 77167 is a prime.

It is a super-2 number, since 2×78191² = 12227664962, which contains 22 as substring.

Together with 78193, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78191.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39095 + 39096.

It is an arithmetic number, because the mean of its divisors is an integer number (39096).

2⁷⁸¹⁹¹ is an apocalyptic number.

78191 is a deficient number, since it is larger than the sum of its proper divisors (1).

78191 is an equidigital number, since it uses as much as digits as its factorization.

78191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 504, while the sum is 26.

The square root of 78191 is about 279.6265366520. The cubic root of 78191 is about 42.7614335092.

The spelling of 78191 in words is "seventy-eight thousand, one hundred ninety-one".