138993407 has 4 divisors (see below), whose sum is σ = 158849616. Its totient is φ = 119137200.

The previous prime is 138993383. The next prime is 138993409. The reversal of 138993407 is 704399831.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 704399831 = 15919 ⋅44249.

It is not a de Polignac number, because 138993407 - 2¹⁶ = 138927871 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 (138993409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9928094 + ... + 9928107.

It is an arithmetic number, because the mean of its divisors is an integer number (39712404).

Almost surely, 2^138993407 is an apocalyptic number.

138993407 is a deficient number, since it is larger than the sum of its proper divisors (19856209).

138993407 is an equidigital number, since it uses as much as digits as its factorization.

138993407 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19856208.

The product of its (nonzero) digits is 163296, while the sum is 44.

The square root of 138993407 is about 11789.5465137553. The cubic root of 138993407 is about 518.0019565824.

The spelling of 138993407 in words is "one hundred thirty-eight million, nine hundred ninety-three thousand, four hundred seven".