128656540 has 12 divisors (see below), whose sum is σ = 270178776. Its totient is φ = 51462608.

The previous prime is 128656537. The next prime is 128656547. The reversal of 128656540 is 45656821.

It is a self number, because there is not a number n which added to its sum of digits gives 128656540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128656547) 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, 3216394 + ... + 3216433.

It is an arithmetic number, because the mean of its divisors is an integer number (22514898).

Almost surely, 2^128656540 is an apocalyptic number.

128656540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128656540 is an abundant number, since it is smaller than the sum of its proper divisors (141522236).

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

128656540 is a wasteful number, since it uses less digits than its factorization.

128656540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6432836 (or 6432834 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 37.

The square root of 128656540 is about 11342.6866306004. The cubic root of 128656540 is about 504.8286056928.

The spelling of 128656540 in words is "one hundred twenty-eight million, six hundred fifty-six thousand, five hundred forty".