77666 has 4 divisors (see below), whose sum is σ = 116502. Its totient is φ = 38832.

The previous prime is 77659. The next prime is 77681. The reversal of 77666 is 66677.

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

It can be written as a sum of positive squares in only one way, i.e., 73441 + 4225 = 271^2 + 65^2 .

It is a Curzon number.

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 77666.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19415 + ... + 19418.

2⁷⁷⁶⁶⁶ is an apocalyptic number.

77666 is a deficient number, since it is larger than the sum of its proper divisors (38836).

77666 is a wasteful number, since it uses less digits than its factorization.

77666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38835.

The product of its digits is 10584, while the sum is 32.

The square root of 77666 is about 278.6862034619. The cubic root of 77666 is about 42.6655137492.

The spelling of 77666 in words is "seventy-seven thousand, six hundred sixty-six".