128206609 has 4 divisors (see below), whose sum is σ = 128356720. Its totient is φ = 128056500.

The previous prime is 128206601. The next prime is 128206633. The reversal of 128206609 is 906602821.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 906602821 = 479 ⋅1892699.

It is a cyclic number.

It is not a de Polignac number, because 128206609 - 2³ = 128206601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128206601) 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, 73767 + ... + 75484.

It is an arithmetic number, because the mean of its divisors is an integer number (32089180).

Almost surely, 2^128206609 is an apocalyptic number.

It is an amenable number.

128206609 is a deficient number, since it is larger than the sum of its proper divisors (150111).

128206609 is an equidigital number, since it uses as much as digits as its factorization.

128206609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150110.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 128206609 is about 11322.8357313881. The cubic root of 128206609 is about 504.2394315150.

The spelling of 128206609 in words is "one hundred twenty-eight million, two hundred six thousand, six hundred nine".