138481729 has 4 divisors (see below), whose sum is σ = 138505300. Its totient is φ = 138458160.

The previous prime is 138481727. The next prime is 138481753. The reversal of 138481729 is 927184831.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 927184831 = 1303 ⋅711577.

It can be written as a sum of positive squares in 2 ways, for example, as 96491329 + 41990400 = 9823^2 + 6480^2 .

It is a cyclic number.

It is not a de Polignac number, because 138481729 - 2¹ = 138481727 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138481727) 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, 4939 + ... + 17359.

It is an arithmetic number, because the mean of its divisors is an integer number (34626325).

Almost surely, 2^138481729 is an apocalyptic number.

It is an amenable number.

138481729 is a deficient number, since it is larger than the sum of its proper divisors (23571).

138481729 is a wasteful number, since it uses less digits than its factorization.

138481729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23570.

The product of its digits is 96768, while the sum is 43.

The square root of 138481729 is about 11767.8260099306. The cubic root of 138481729 is about 517.3655328321.

The spelling of 138481729 in words is "one hundred thirty-eight million, four hundred eighty-one thousand, seven hundred twenty-nine".