77857 has 8 divisors (see below), whose sum is σ = 86184. Its totient is φ = 69888.

The previous prime is 77849. The next prime is 77863. The reversal of 77857 is 75877.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16 + 77841 = 4^2 + 279^2 .

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

It is not a de Polignac number, because 77857 - 2³ = 77849 is a prime.

It is a Duffinian number.

77857 is a lucky 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 7 ways as a sum of consecutive naturals, for example, 633 + ... + 745.

It is an arithmetic number, because the mean of its divisors is an integer number (10773).

2⁷⁷⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

77857 is a deficient number, since it is larger than the sum of its proper divisors (8327).

77857 is a wasteful number, since it uses less digits than its factorization.

77857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179.

The product of its digits is 13720, while the sum is 34.

The square root of 77857 is about 279.0286723618. The cubic root of 77857 is about 42.7004601522.

The spelling of 77857 in words is "seventy-seven thousand, eight hundred fifty-seven".