128909646 has 24 divisors (see below), whose sum is σ = 279933264. Its totient is φ = 42873120.

The previous prime is 128909639. The next prime is 128909663. The reversal of 128909646 is 646909821.

It is a happy number.

It is a congruent number.

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, 391 + ... + 16061.

It is an arithmetic number, because the mean of its divisors is an integer number (11663886).

Almost surely, 2^128909646 is an apocalyptic number.

128909646 is an abundant number, since it is smaller than the sum of its proper divisors (151023618).

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

128909646 is a wasteful number, since it uses less digits than its factorization.

128909646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16136 (or 16133 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 45.

The square root of 128909646 is about 11353.8383817985. The cubic root of 128909646 is about 505.1594385957.

The spelling of 128909646 in words is "one hundred twenty-eight million, nine hundred nine thousand, six hundred forty-six".