78842191 has 4 divisors (see below), whose sum is σ = 82991800. Its totient is φ = 74692584.

The previous prime is 78842189. The next prime is 78842249. The reversal of 78842191 is 19124887.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 78842191 - 2¹ = 78842189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78842591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2074776 + ... + 2074813.

It is an arithmetic number, because the mean of its divisors is an integer number (20747950).

Almost surely, 2^78842191 is an apocalyptic number.

78842191 is a deficient number, since it is larger than the sum of its proper divisors (4149609).

78842191 is a wasteful number, since it uses less digits than its factorization.

78842191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4149608.

The product of its digits is 32256, while the sum is 40.

The square root of 78842191 is about 8879.3125296951. The cubic root of 78842191 is about 428.7981420214.

The spelling of 78842191 in words is "seventy-eight million, eight hundred forty-two thousand, one hundred ninety-one".