138904445 has 4 divisors (see below), whose sum is σ = 166685340. Its totient is φ = 111123552.

The previous prime is 138904439. The next prime is 138904453. The reversal of 138904445 is 544409831.

138904445 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26925721 + 111978724 = 5189^2 + 10582^2 .

It is a cyclic number.

It is not a de Polignac number, because 138904445 - 2¹⁰ = 138903421 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 138904399 and 138904408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13890440 + ... + 13890449.

It is an arithmetic number, because the mean of its divisors is an integer number (41671335).

Almost surely, 2^138904445 is an apocalyptic number.

It is an amenable number.

138904445 is a deficient number, since it is larger than the sum of its proper divisors (27780895).

138904445 is an equidigital number, since it uses as much as digits as its factorization.

138904445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27780894.

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 138904445 is about 11785.7729911958. The cubic root of 138904445 is about 517.8914181855.

The spelling of 138904445 in words is "one hundred thirty-eight million, nine hundred four thousand, four hundred forty-five".