138857 has 4 divisors (see below), whose sum is σ = 139776. Its totient is φ = 137940.

The previous prime is 138841. The next prime is 138863. The reversal of 138857 is 758831.

138857 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 758831 = 97 ⋅7823.

It is a cyclic number.

It is not a de Polignac number, because 138857 - 2⁴ = 138841 is a prime.

It is a Duffinian number.

It is a plaindrome in base 7.

It is a zygodrome in base 7.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 138857.

It is not an unprimeable number, because it can be changed into a prime (138157) 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, 173 + ... + 554.

It is an arithmetic number, because the mean of its divisors is an integer number (34944).

2¹³⁸⁸⁵⁷ is an apocalyptic number.

It is an amenable number.

138857 is a deficient number, since it is larger than the sum of its proper divisors (919).

138857 is an equidigital number, since it uses as much as digits as its factorization.

138857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918.

The product of its digits is 6720, while the sum is 32.

The square root of 138857 is about 372.6352103599. The cubic root of 138857 is about 51.7832446815.

The spelling of 138857 in words is "one hundred thirty-eight thousand, eight hundred fifty-seven".