138401 has 2 divisors, whose sum is σ = 138402. Its totient is φ = 138400.

The previous prime is 138389. The next prime is 138403. The reversal of 138401 is 104831.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115600 + 22801 = 340^2 + 151^2 .

It is an emirp because it is prime and its reverse (104831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138401 - 2⁶ = 138337 is a prime.

Together with 138403, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 138401.

It is not a weakly prime, because it can be changed into another prime (138403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69200 + 69201.

It is an arithmetic number, because the mean of its divisors is an integer number (69201).

2¹³⁸⁴⁰¹ is an apocalyptic number.

It is an amenable number.

138401 is a deficient number, since it is larger than the sum of its proper divisors (1).

138401 is an equidigital number, since it uses as much as digits as its factorization.

138401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 138401 is about 372.0228487607. The cubic root of 138401 is about 51.7264979204.

Subtracting from 138401 its sum of digits (17), we obtain a square (138384 = 372²).

The spelling of 138401 in words is "one hundred thirty-eight thousand, four hundred one".