77827 has 4 divisors (see below), whose sum is σ = 78400. Its totient is φ = 77256.

The previous prime is 77813. The next prime is 77839. The reversal of 77827 is 72877.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 77827 - 2⁷ = 77699 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 (77867) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 49 + ... + 397.

It is an arithmetic number, because the mean of its divisors is an integer number (19600).

2⁷⁷⁸²⁷ is an apocalyptic number.

77827 is a deficient number, since it is larger than the sum of its proper divisors (573).

77827 is a wasteful number, since it uses less digits than its factorization.

77827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572.

The product of its digits is 5488, while the sum is 31.

The square root of 77827 is about 278.9749092660. The cubic root of 77827 is about 42.6949749748.

Subtracting from 77827 its reverse (72877), we obtain a triangular number (4950 = T₉₉).

The spelling of 77827 in words is "seventy-seven thousand, eight hundred twenty-seven".