77666165 has 4 divisors (see below), whose sum is σ = 93199404. Its totient is φ = 62132928.

The previous prime is 77666159. The next prime is 77666179. The reversal of 77666165 is 56166677.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56166677 = 7 ⋅8023811.

It can be written as a sum of positive squares in 2 ways, for example, as 21446161 + 56220004 = 4631^2 + 7498^2 .

It is a cyclic number.

It is not a de Polignac number, because 77666165 - 2⁸ = 77665909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 7766612 + ... + 7766621.

It is an arithmetic number, because the mean of its divisors is an integer number (23299851).

Almost surely, 2^77666165 is an apocalyptic number.

It is an amenable number.

77666165 is a deficient number, since it is larger than the sum of its proper divisors (15533239).

77666165 is a wasteful number, since it uses less digits than its factorization.

77666165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15533238.

The product of its digits is 317520, while the sum is 44.

The square root of 77666165 is about 8812.8409153916. The cubic root of 77666165 is about 426.6554396324.

It can be divided in two parts, 7766 and 6165, that added together give a palindrome (13931).

The spelling of 77666165 in words is "seventy-seven million, six hundred sixty-six thousand, one hundred sixty-five".