128538240 has 64 divisors (see below), whose sum is σ = 409721760. Its totient is φ = 34276352.

The previous prime is 128538217. The next prime is 128538251. The reversal of 128538240 is 42835821.

It is a tau number, because it is divible by the number of its divisors (64).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31554 + ... + 35393.

Almost surely, 2^128538240 is an apocalyptic number.

128538240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128538240 is an abundant number, since it is smaller than the sum of its proper divisors (281183520).

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

128538240 is an equidigital number, since it uses as much as digits as its factorization.

128538240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66969 (or 66957 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 33.

The square root of 128538240 is about 11337.4706173820. The cubic root of 128538240 is about 504.6738278685.

It can be divided in two parts, 128538 and 240, that added together give a triangular number (128778 = T₅₀₇).

The spelling of 128538240 in words is "one hundred twenty-eight million, five hundred thirty-eight thousand, two hundred forty".