128512609 has 2 divisors, whose sum is σ = 128512610. Its totient is φ = 128512608.

The previous prime is 128512607. The next prime is 128512613. The reversal of 128512609 is 906215821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77704225 + 50808384 = 8815^2 + 7128^2 .

It is a cyclic number.

It is not a de Polignac number, because 128512609 - 2¹ = 128512607 is a prime.

Together with 128512607, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (128512607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64256304 + 64256305.

It is an arithmetic number, because the mean of its divisors is an integer number (64256305).

Almost surely, 2^128512609 is an apocalyptic number.

It is an amenable number.

128512609 is a deficient number, since it is larger than the sum of its proper divisors (1).

128512609 is an equidigital number, since it uses as much as digits as its factorization.

128512609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 34.

The square root of 128512609 is about 11336.3401942602. The cubic root of 128512609 is about 504.6402810299.

The spelling of 128512609 in words is "one hundred twenty-eight million, five hundred twelve thousand, six hundred nine".