77916191 has 4 divisors (see below), whose sum is σ = 80022072. Its totient is φ = 75810312.

The previous prime is 77916187. The next prime is 77916211. The reversal of 77916191 is 19161977.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19161977 = 71 ⋅269887.

It is a cyclic number.

It is not a de Polignac number, because 77916191 - 2² = 77916187 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 (77916121) 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, 1052885 + ... + 1052958.

It is an arithmetic number, because the mean of its divisors is an integer number (20005518).

Almost surely, 2^77916191 is an apocalyptic number.

77916191 is a deficient number, since it is larger than the sum of its proper divisors (2105881).

77916191 is a wasteful number, since it uses less digits than its factorization.

77916191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2105880.

The product of its digits is 23814, while the sum is 41.

The square root of 77916191 is about 8827.0148408168. The cubic root of 77916191 is about 427.1127845886.

The spelling of 77916191 in words is "seventy-seven million, nine hundred sixteen thousand, one hundred ninety-one".