138478506 has 32 divisors (see below), whose sum is σ = 283201920. Its totient is φ = 45125184.

The previous prime is 138478493. The next prime is 138478507. The reversal of 138478506 is 605874831.

138478506 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (138478507) 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, 113556 + ... + 114768.

It is an arithmetic number, because the mean of its divisors is an integer number (8850060).

Almost surely, 2^138478506 is an apocalyptic number.

138478506 is an abundant number, since it is smaller than the sum of its proper divisors (144723414).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

138478506 is a wasteful number, since it uses less digits than its factorization.

138478506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1630.

The product of its (nonzero) digits is 161280, while the sum is 42.

The square root of 138478506 is about 11767.6890679521. The cubic root of 138478506 is about 517.3615191087.

The spelling of 138478506 in words is "one hundred thirty-eight million, four hundred seventy-eight thousand, five hundred six".