77666879 has 4 divisors (see below), whose sum is σ = 78435960. Its totient is φ = 76897800.

The previous prime is 77666819. The next prime is 77666891. The reversal of 77666879 is 97866677.

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

It is a cyclic number.

It is not a de Polignac number, because 77666879 - 2²⁴ = 60889663 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 (77666819) 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, 384389 + ... + 384590.

It is an arithmetic number, because the mean of its divisors is an integer number (19608990).

Almost surely, 2^77666879 is an apocalyptic number.

77666879 is a deficient number, since it is larger than the sum of its proper divisors (769081).

77666879 is a wasteful number, since it uses less digits than its factorization.

77666879 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769080.

The product of its digits is 5334336, while the sum is 56.

The square root of 77666879 is about 8812.8814243697. The cubic root of 77666879 is about 426.6567470703.

The spelling of 77666879 in words is "seventy-seven million, six hundred sixty-six thousand, eight hundred seventy-nine".