128450809 has 4 divisors (see below), whose sum is σ = 128538000. Its totient is φ = 128363620.

The previous prime is 128450807. The next prime is 128450821. The reversal of 128450809 is 908054821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128450809 - 2¹ = 128450807 is a prime.

It is a super-2 number, since 2×128450809² = 32999220665508962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128450801) 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, 41347 + ... + 44344.

It is an arithmetic number, because the mean of its divisors is an integer number (32134500).

Almost surely, 2^128450809 is an apocalyptic number.

It is an amenable number.

128450809 is a deficient number, since it is larger than the sum of its proper divisors (87191).

128450809 is an equidigital number, since it uses as much as digits as its factorization.

128450809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87190.

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 128450809 is about 11333.6141190708. The cubic root of 128450809 is about 504.5593764659.

The spelling of 128450809 in words is "one hundred twenty-eight million, four hundred fifty thousand, eight hundred nine".