138481481 has 4 divisors (see below), whose sum is σ = 145770000. Its totient is φ = 131192964.

The previous prime is 138481451. The next prime is 138481487. The reversal of 138481481 is 184184831.

It is a happy number.

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: 184184831 = 839 ⋅219529.

It is a cyclic number.

It is not a de Polignac number, because 138481481 - 2¹⁰ = 138480457 is a prime.

It is a super-2 number, since 2×138481481² = 38354241159906722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138481487) 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, 3644231 + ... + 3644268.

It is an arithmetic number, because the mean of its divisors is an integer number (36442500).

Almost surely, 2^138481481 is an apocalyptic number.

It is an amenable number.

138481481 is a deficient number, since it is larger than the sum of its proper divisors (7288519).

138481481 is an equidigital number, since it uses as much as digits as its factorization.

138481481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7288518.

The product of its digits is 24576, while the sum is 38.

The square root of 138481481 is about 11767.8154727205. The cubic root of 138481481 is about 517.3652239905.

The spelling of 138481481 in words is "one hundred thirty-eight million, four hundred eighty-one thousand, four hundred eighty-one".