78666861 has 32 divisors (see below), whose sum is σ = 131862528. Its totient is φ = 40605120.

The previous prime is 78666829. The next prime is 78666869. The reversal of 78666861 is 16866687.

It is not a de Polignac number, because 78666861 - 2⁵ = 78666829 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 78666861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78666869) 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 31 ways as a sum of consecutive naturals, for example, 9766 + ... + 15896.

It is an arithmetic number, because the mean of its divisors is an integer number (4120704).

Almost surely, 2^78666861 is an apocalyptic number.

It is an amenable number.

78666861 is a deficient number, since it is larger than the sum of its proper divisors (53195667).

78666861 is a wasteful number, since it uses less digits than its factorization.

78666861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6201.

The product of its digits is 580608, while the sum is 48.

The square root of 78666861 is about 8869.4340856675. The cubic root of 78666861 is about 428.4800510104.

It can be divided in two parts, 7866686 and 1, that added together give a palindrome (7866687).

The spelling of 78666861 in words is "seventy-eight million, six hundred sixty-six thousand, eight hundred sixty-one".