138257 has 4 divisors (see below), whose sum is σ = 158016. Its totient is φ = 118500.

The previous prime is 138251. The next prime is 138283. The reversal of 138257 is 752831.

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.

It is a cyclic number.

It is not a de Polignac number, because 138257 - 2⁴ = 138241 is a prime.

It is a super-2 number, since 2×138257² = 38229996098, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138251) 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, 9869 + ... + 9882.

It is an arithmetic number, because the mean of its divisors is an integer number (39504).

2¹³⁸²⁵⁷ is an apocalyptic number.

It is an amenable number.

138257 is a deficient number, since it is larger than the sum of its proper divisors (19759).

138257 is an equidigital number, since it uses as much as digits as its factorization.

138257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19758.

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

The square root of 138257 is about 371.8292618931. The cubic root of 138257 is about 51.7085519988.

The spelling of 138257 in words is "one hundred thirty-eight thousand, two hundred fifty-seven".