138378613 has 4 divisors (see below), whose sum is σ = 138445740. Its totient is φ = 138311488.

The previous prime is 138378607. The next prime is 138378619. The reversal of 138378613 is 316873831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 316873831 = 83 ⋅3817757.

It is an interprime number because it is at equal distance from previous prime (138378607) and next prime (138378619).

It can be written as a sum of positive squares in 2 ways, for example, as 25020004 + 113358609 = 5002^2 + 10647^2 .

It is a cyclic number.

It is not a de Polignac number, because 138378613 - 2¹⁷ = 138247541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138378619) 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, 30370 + ... + 34627.

It is an arithmetic number, because the mean of its divisors is an integer number (34611435).

Almost surely, 2^138378613 is an apocalyptic number.

It is an amenable number.

138378613 is a deficient number, since it is larger than the sum of its proper divisors (67127).

138378613 is an equidigital number, since it uses as much as digits as its factorization.

138378613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67126.

The product of its digits is 72576, while the sum is 40.

The square root of 138378613 is about 11763.4439259938. The cubic root of 138378613 is about 517.2370877017.

The spelling of 138378613 in words is "one hundred thirty-eight million, three hundred seventy-eight thousand, six hundred thirteen".