138961 has 4 divisors (see below), whose sum is σ = 140800. Its totient is φ = 137124.

The previous prime is 138959. The next prime is 138967. The reversal of 138961 is 169831.

It is a happy number.

138961 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.

It is a cyclic number.

It is not a de Polignac number, because 138961 - 2¹ = 138959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138967) 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, 801 + ... + 958.

It is an arithmetic number, because the mean of its divisors is an integer number (35200).

2¹³⁸⁹⁶¹ is an apocalyptic number.

It is an amenable number.

138961 is a deficient number, since it is larger than the sum of its proper divisors (1839).

138961 is an equidigital number, since it uses as much as digits as its factorization.

138961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1838.

The product of its digits is 1296, while the sum is 28.

The square root of 138961 is about 372.7747309033. The cubic root of 138961 is about 51.7961695214.

The spelling of 138961 in words is "one hundred thirty-eight thousand, nine hundred sixty-one".