7857 has 10 divisors (see below), whose sum is σ = 11858. Its totient is φ = 5184.

The previous prime is 7853. The next prime is 7867. The reversal of 7857 is 7587.

It can be written as a sum of positive squares in only one way, i.e., 6561 + 1296 = 81^2 + 36^2 .

It is not a de Polignac number, because 7857 - 2² = 7853 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a plaindrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 7857.

It is not an unprimeable number, because it can be changed into a prime (7853) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 33 + ... + 129.

2⁷⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

7857 is a deficient number, since it is larger than the sum of its proper divisors (4001).

7857 is an equidigital number, since it uses as much as digits as its factorization.

7857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 100 counting only the distinct ones).

The product of its digits is 1960, while the sum is 27.

The square root of 7857 is about 88.6397202162. The cubic root of 7857 is about 19.8801161624.

The spelling of 7857 in words is "seven thousand, eight hundred fifty-seven".