138431407 has 4 divisors (see below), whose sum is σ = 138942496. Its totient is φ = 137920320.

The previous prime is 138431383. The next prime is 138431437. The reversal of 138431407 is 704134831.

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

It is a cyclic number.

It is not a de Polignac number, because 138431407 - 2¹¹ = 138429359 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138431437) 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, 255138 + ... + 255679.

It is an arithmetic number, because the mean of its divisors is an integer number (34735624).

Almost surely, 2^138431407 is an apocalyptic number.

138431407 is a deficient number, since it is larger than the sum of its proper divisors (511089).

138431407 is an equidigital number, since it uses as much as digits as its factorization.

138431407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 511088.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 138431407 is about 11765.6876977081. The cubic root of 138431407 is about 517.3028578431.

The spelling of 138431407 in words is "one hundred thirty-eight million, four hundred thirty-one thousand, four hundred seven".