123857 has 4 divisors (see below), whose sum is σ = 124656. Its totient is φ = 123060.

The previous prime is 123853. The next prime is 123863. The reversal of 123857 is 758321.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, 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 123857 - 2² = 123853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (123853) 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, 83 + ... + 504.

It is an arithmetic number, because the mean of its divisors is an integer number (31164).

2¹²³⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

123857 is a deficient number, since it is larger than the sum of its proper divisors (799).

123857 is an equidigital number, since it uses as much as digits as its factorization.

123857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798.

The product of its digits is 1680, while the sum is 26.

The square root of 123857 is about 351.9332323041. The cubic root of 123857 is about 49.8471331106.

The spelling of 123857 in words is "one hundred twenty-three thousand, eight hundred fifty-seven".