138486409 has 4 divisors (see below), whose sum is σ = 140756740. Its totient is φ = 136216080.

The previous prime is 138486407. The next prime is 138486419. The reversal of 138486409 is 904684831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 904684831 = 2579 ⋅350789.

It can be written as a sum of positive squares in 2 ways, for example, as 25000000 + 113486409 = 5000^2 + 10653^2 .

It is a cyclic number.

It is not a de Polignac number, because 138486409 - 2¹ = 138486407 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138486401) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1135074 + ... + 1135195.

It is an arithmetic number, because the mean of its divisors is an integer number (35189185).

Almost surely, 2^138486409 is an apocalyptic number.

It is an amenable number.

138486409 is a deficient number, since it is larger than the sum of its proper divisors (2270331).

138486409 is an equidigital number, since it uses as much as digits as its factorization.

138486409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2270330.

The product of its (nonzero) digits is 165888, while the sum is 43.

The square root of 138486409 is about 11768.0248555142. The cubic root of 138486409 is about 517.3713609016.

The spelling of 138486409 in words is "one hundred thirty-eight million, four hundred eighty-six thousand, four hundred nine".