138072581 has 4 divisors (see below), whose sum is σ = 138103392. Its totient is φ = 138041772.

The previous prime is 138072547. The next prime is 138072593. The reversal of 138072581 is 185270831.

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 138072581 - 2¹⁴ = 138056197 is a prime.

It is a super-2 number, since 2×138072581² = 38128075248003122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138072881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7241 + ... + 18126.

It is an arithmetic number, because the mean of its divisors is an integer number (34525848).

Almost surely, 2^138072581 is an apocalyptic number.

It is an amenable number.

138072581 is a deficient number, since it is larger than the sum of its proper divisors (30811).

138072581 is an equidigital number, since it uses as much as digits as its factorization.

138072581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30810.

The product of its (nonzero) digits is 13440, while the sum is 35.

The square root of 138072581 is about 11750.4289708929. The cubic root of 138072581 is about 516.8555067371.

The spelling of 138072581 in words is "one hundred thirty-eight million, seventy-two thousand, five hundred eighty-one".