128406656 has 96 divisors (see below), whose sum is σ = 303490800. Its totient is φ = 53942784.

The previous prime is 128406637. The next prime is 128406667. The reversal of 128406656 is 656604821.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 369875 + ... + 370221.

Almost surely, 2^128406656 is an apocalyptic number.

128406656 is a gapful number since it is divisible by the number (16) 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 128406656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (151745400).

128406656 is an abundant number, since it is smaller than the sum of its proper divisors (175084144).

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

128406656 is an equidigital number, since it uses as much as digits as its factorization.

128406656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 434 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 38.

The square root of 128406656 is about 11331.6660734422. Note that the first 3 decimals coincide. The cubic root of 128406656 is about 504.5015583191.

The spelling of 128406656 in words is "one hundred twenty-eight million, four hundred six thousand, six hundred fifty-six".