77687 has 2 divisors, whose sum is σ = 77688. Its totient is φ = 77686.

The previous prime is 77681. The next prime is 77689. The reversal of 77687 is 78677.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 77687 - 2⁸ = 77431 is a prime.

Together with 77689, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38843 + 38844.

It is an arithmetic number, because the mean of its divisors is an integer number (38844).

2⁷⁷⁶⁸⁷ is an apocalyptic number.

77687 is a deficient number, since it is larger than the sum of its proper divisors (1).

77687 is an equidigital number, since it uses as much as digits as its factorization.

77687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16464, while the sum is 35.

The square root of 77687 is about 278.7238776998. The cubic root of 77687 is about 42.6693588254.

Subtracting 77687 from its reverse (78677), we obtain a triangular number (990 = T₄₄).

The spelling of 77687 in words is "seventy-seven thousand, six hundred eighty-seven".