138628815 has 16 divisors (see below), whose sum is σ = 238868448. Its totient is φ = 68247936.

The previous prime is 138628801. The next prime is 138628817. The reversal of 138628815 is 518826831.

138628815 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 138628815 - 2¹¹ = 138626767 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138628817) 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, 355264 + ... + 355653.

It is an arithmetic number, because the mean of its divisors is an integer number (14929278).

Almost surely, 2^138628815 is an apocalyptic number.

138628815 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

138628815 is a deficient number, since it is larger than the sum of its proper divisors (100239633).

138628815 is a wasteful number, since it uses less digits than its factorization.

138628815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710938.

The product of its digits is 92160, while the sum is 42.

The square root of 138628815 is about 11774.0738489276. The cubic root of 138628815 is about 517.5486383373.

The spelling of 138628815 in words is "one hundred thirty-eight million, six hundred twenty-eight thousand, eight hundred fifteen".