138128656 has 20 divisors (see below), whose sum is σ = 271014400. Its totient is φ = 68189472.

The previous prime is 138128647. The next prime is 138128657. The reversal of 138128656 is 656821831.

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 3 ways as a sum of consecutive naturals, for example, 53376 + ... + 55903.

It is an arithmetic number, because the mean of its divisors is an integer number (13550720).

Almost surely, 2^138128656 is an apocalyptic number.

138128656 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

138128656 is a deficient number, since it is larger than the sum of its proper divisors (132885744).

138128656 is a wasteful number, since it uses less digits than its factorization.

138128656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109366 (or 109360 counting only the distinct ones).

The product of its digits is 69120, while the sum is 40.

The square root of 138128656 is about 11752.8148117802. The cubic root of 138128656 is about 516.9254669220.

The spelling of 138128656 in words is "one hundred thirty-eight million, one hundred twenty-eight thousand, six hundred fifty-six".