128240640 has 396 divisors, whose sum is σ = 509653872. Its totient is φ = 29736960.

The previous prime is 128240627. The next prime is 128240657. The reversal of 128240640 is 46042821.

128240640 is a `hidden beast` number, since 12 + 8 + 2 + 4 + 0 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (396).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5575669 + ... + 5575691.

Almost surely, 2^128240640 is an apocalyptic number.

128240640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 128240640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (254826936).

128240640 is an abundant number, since it is smaller than the sum of its proper divisors (381413232).

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

128240640 is a wasteful number, since it uses less digits than its factorization.

128240640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76 (or 44 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 128240640 is about 11324.3383912704. The cubic root of 128240640 is about 504.2840424602.

The spelling of 128240640 in words is "one hundred twenty-eight million, two hundred forty thousand, six hundred forty".