138128655 has 32 divisors (see below), whose sum is σ = 267439104. Its totient is φ = 59429376.

The previous prime is 138128647. The next prime is 138128657. The reversal of 138128655 is 556821831.

It is not a de Polignac number, because 138128655 - 2³ = 138128647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (138128657) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 36907 + ... + 40476.

It is an arithmetic number, because the mean of its divisors is an integer number (8357472).

Almost surely, 2^138128655 is an apocalyptic number.

138128655 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

138128655 is a deficient number, since it is larger than the sum of its proper divisors (129310449).

138128655 is a wasteful number, since it uses less digits than its factorization.

138128655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77415.

The product of its digits is 57600, while the sum is 39.

The square root of 138128655 is about 11752.8147692372. The cubic root of 138128655 is about 516.9254656745.

The spelling of 138128655 in words is "one hundred thirty-eight million, one hundred twenty-eight thousand, six hundred fifty-five".