77856857 has 4 divisors (see below), whose sum is σ = 83845860. Its totient is φ = 71867856.

The previous prime is 77856829. The next prime is 77856859. The reversal of 77856857 is 75865877.

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

It can be written as a sum of positive squares in 2 ways, for example, as 32307856 + 45549001 = 5684^2 + 6749^2 .

It is a cyclic number.

It is not a de Polignac number, because 77856857 - 2⁸ = 77856601 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77856799 and 77856808.

It is not an unprimeable number, because it can be changed into a prime (77856859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2994482 + ... + 2994507.

It is an arithmetic number, because the mean of its divisors is an integer number (20961465).

Almost surely, 2^77856857 is an apocalyptic number.

It is an amenable number.

77856857 is a deficient number, since it is larger than the sum of its proper divisors (5989003).

77856857 is a wasteful number, since it uses less digits than its factorization.

77856857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5989002.

The product of its digits is 3292800, while the sum is 53.

The square root of 77856857 is about 8823.6532683464. The cubic root of 77856857 is about 427.0043400956.

The spelling of 77856857 in words is "seventy-seven million, eight hundred fifty-six thousand, eight hundred fifty-seven".