128509845 has 16 divisors (see below), whose sum is σ = 206128320. Its totient is φ = 68367744.

The previous prime is 128509841. The next prime is 128509861. The reversal of 128509845 is 548905821.

It is a happy number.

It is not a de Polignac number, because 128509845 - 2² = 128509841 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 128509797 and 128509806.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128509841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4339 + ... + 16608.

It is an arithmetic number, because the mean of its divisors is an integer number (12883020).

Almost surely, 2^128509845 is an apocalyptic number.

128509845 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128509845 is a deficient number, since it is larger than the sum of its proper divisors (77618475).

128509845 is a wasteful number, since it uses less digits than its factorization.

128509845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21364.

The product of its (nonzero) digits is 115200, while the sum is 42.

The square root of 128509845 is about 11336.2182847720. The cubic root of 128509845 is about 504.6366631340.

The spelling of 128509845 in words is "one hundred twenty-eight million, five hundred nine thousand, eight hundred forty-five".