138509825 has 6 divisors (see below), whose sum is σ = 171752214. Its totient is φ = 110807840.

The previous prime is 138509807. The next prime is 138509827. The reversal of 138509825 is 528905831.

It can be written as a sum of positive squares in 3 ways, for example, as 588289 + 137921536 = 767^2 + 11744^2 .

It is not a de Polignac number, because 138509825 - 2²⁰ = 137461249 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (138509827) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2770172 + ... + 2770221.

It is an arithmetic number, because the mean of its divisors is an integer number (28625369).

Almost surely, 2^138509825 is an apocalyptic number.

It is an amenable number.

138509825 is a deficient number, since it is larger than the sum of its proper divisors (33242389).

138509825 is an equidigital number, since it uses as much as digits as its factorization.

138509825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5540403 (or 5540398 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 41.

The square root of 138509825 is about 11769.0197127883. The cubic root of 138509825 is about 517.4005192022.

The spelling of 138509825 in words is "one hundred thirty-eight million, five hundred nine thousand, eight hundred twenty-five".