138478915 has 16 divisors (see below), whose sum is σ = 173184480. Its totient is φ = 106167040.

The previous prime is 138478913. The next prime is 138478919. The reversal of 138478915 is 519874831.

It is a happy number.

It is not a de Polignac number, because 138478915 - 2¹ = 138478913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (138478913) 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, 16380 + ... + 23350.

It is an arithmetic number, because the mean of its divisors is an integer number (10824030).

Almost surely, 2^138478915 is an apocalyptic number.

138478915 is a deficient number, since it is larger than the sum of its proper divisors (34705565).

138478915 is a wasteful number, since it uses less digits than its factorization.

138478915 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7142.

The product of its digits is 241920, while the sum is 46.

The square root of 138478915 is about 11767.7064460327. The cubic root of 138478915 is about 517.3620284553.

The spelling of 138478915 in words is "one hundred thirty-eight million, four hundred seventy-eight thousand, nine hundred fifteen".