138403 has 2 divisors, whose sum is σ = 138404. Its totient is φ = 138402.

The previous prime is 138401. The next prime is 138407. The reversal of 138403 is 304831.

It is a weak prime.

It is an emirp because it is prime and its reverse (304831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138403 - 2¹ = 138401 is a prime.

Together with 138401, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (138401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69201 + 69202.

It is an arithmetic number, because the mean of its divisors is an integer number (69202).

2¹³⁸⁴⁰³ is an apocalyptic number.

138403 is a deficient number, since it is larger than the sum of its proper divisors (1).

138403 is an equidigital number, since it uses as much as digits as its factorization.

138403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 138403 is about 372.0255367579. The cubic root of 138403 is about 51.7267470817.

Subtracting from 138403 its sum of digits (19), we obtain a square (138384 = 372²).

The spelling of 138403 in words is "one hundred thirty-eight thousand, four hundred three".