78687666 has 32 divisors (see below), whose sum is σ = 175893120. Its totient is φ = 26074512.

The previous prime is 78687647. The next prime is 78687671. The reversal of 78687666 is 66678687.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon 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 15 ways as a sum of consecutive naturals, for example, 5131 + ... + 13553.

It is an arithmetic number, because the mean of its divisors is an integer number (5496660).

Almost surely, 2^78687666 is an apocalyptic number.

78687666 is an abundant number, since it is smaller than the sum of its proper divisors (97205454).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78687666 is a wasteful number, since it uses less digits than its factorization.

78687666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8607 (or 8601 counting only the distinct ones).

The product of its digits is 4064256, while the sum is 54.

The square root of 78687666 is about 8870.6068563543. The cubic root of 78687666 is about 428.5178210091.

The spelling of 78687666 in words is "seventy-eight million, six hundred eighty-seven thousand, six hundred sixty-six".