77987 has 8 divisors (see below), whose sum is σ = 96096. Its totient is φ = 61632.

The previous prime is 77983. The next prime is 77999. The reversal of 77987 is 78977.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77987 - 2² = 77983 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77987.

It is not an unprimeable number, because it can be changed into a prime (77983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338 + ... + 519.

It is an arithmetic number, because the mean of its divisors is an integer number (12012).

2⁷⁷⁹⁸⁷ is an apocalyptic number.

77987 is a deficient number, since it is larger than the sum of its proper divisors (18109).

77987 is a wasteful number, since it uses less digits than its factorization.

77987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 877.

The product of its digits is 24696, while the sum is 38.

The square root of 77987 is about 279.2615261722. The cubic root of 77987 is about 42.7242129858.

Subtracting 77987 from its reverse (78977), we obtain a triangular number (990 = T₄₄).

The spelling of 77987 in words is "seventy-seven thousand, nine hundred eighty-seven".