138205481 has 4 divisors (see below), whose sum is σ = 138241152. Its totient is φ = 138169812.

The previous prime is 138205451. The next prime is 138205489. The reversal of 138205481 is 184502831.

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 138205481 - 2¹⁴ = 138189097 is a prime.

It is a super-2 number, since 2×138205481² = 38201509956882722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138205489) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11201 + ... + 20046.

It is an arithmetic number, because the mean of its divisors is an integer number (34560288).

Almost surely, 2^138205481 is an apocalyptic number.

It is an amenable number.

138205481 is a deficient number, since it is larger than the sum of its proper divisors (35671).

138205481 is an equidigital number, since it uses as much as digits as its factorization.

138205481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35670.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 138205481 is about 11756.0827234245. The cubic root of 138205481 is about 517.0212844491.

The spelling of 138205481 in words is "one hundred thirty-eight million, two hundred five thousand, four hundred eighty-one".