128896640 has 32 divisors (see below), whose sum is σ = 308145060. Its totient is φ = 51558400.

The previous prime is 128896613. The next prime is 128896643. The reversal of 128896640 is 46698821.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 120648256 + 8248384 = 10984^2 + 2872^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×128896640² = 33228687606579200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 128896591 and 128896600.

It is not an unprimeable number, because it can be changed into a prime (128896643) 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, 100061 + ... + 101340.

Almost surely, 2^128896640 is an apocalyptic number.

128896640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128896640 is an abundant number, since it is smaller than the sum of its proper divisors (179248420).

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

128896640 is an equidigital number, since it uses as much as digits as its factorization.

128896640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201420 (or 201408 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 128896640 is about 11353.2656095064. The cubic root of 128896640 is about 505.1424491130.

The spelling of 128896640 in words is "one hundred twenty-eight million, eight hundred ninety-six thousand, six hundred forty".