138657 has 4 divisors (see below), whose sum is σ = 184880. Its totient is φ = 92436.

The previous prime is 138647. The next prime is 138661. The reversal of 138657 is 756831.

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 an emirpimes, since its reverse is a distinct semiprime: 756831 = 3 ⋅252277.

It is not a de Polignac number, because 138657 - 2⁴ = 138641 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138617) 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, 23107 + ... + 23112.

It is an arithmetic number, because the mean of its divisors is an integer number (46220).

2¹³⁸⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

138657 is a deficient number, since it is larger than the sum of its proper divisors (46223).

138657 is an equidigital number, since it uses as much as digits as its factorization.

138657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46222.

The product of its digits is 5040, while the sum is 30.

The square root of 138657 is about 372.3667546922. The cubic root of 138657 is about 51.7583710699.

The spelling of 138657 in words is "one hundred thirty-eight thousand, six hundred fifty-seven".