138965409 has 16 divisors (see below), whose sum is σ = 224591040. Its totient is φ = 84221280.

The previous prime is 138965369. The next prime is 138965413. The reversal of 138965409 is 904569831.

It is a happy number.

138965409 is a `hidden beast` number, since 13 + 8 + 96 + 540 + 9 = 666.

It is not a de Polignac number, because 138965409 - 2²³ = 130576801 is a prime.

It is a super-2 number, since 2×138965409² = 38622769797074562, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (138965009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 233652 + ... + 234245.

It is an arithmetic number, because the mean of its divisors is an integer number (14036940).

Almost surely, 2^138965409 is an apocalyptic number.

It is an amenable number.

138965409 is a deficient number, since it is larger than the sum of its proper divisors (85625631).

138965409 is a wasteful number, since it uses less digits than its factorization.

138965409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 467917 (or 467911 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 138965409 is about 11788.3590461099. The cubic root of 138965409 is about 517.9671731755.

The spelling of 138965409 in words is "one hundred thirty-eight million, nine hundred sixty-five thousand, four hundred nine".