128512643 has 6 divisors (see below), whose sum is σ = 149494356. Its totient is φ = 110153652.

The previous prime is 128512621. The next prime is 128512669. The reversal of 128512643 is 346215821.

It is not a de Polignac number, because 128512643 - 2⁸ = 128512387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128512613) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1311305 + ... + 1311402.

It is an arithmetic number, because the mean of its divisors is an integer number (24915726).

Almost surely, 2^128512643 is an apocalyptic number.

128512643 is a deficient number, since it is larger than the sum of its proper divisors (20981713).

128512643 is an equidigital number, since it uses as much as digits as its factorization.

128512643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2622721 (or 2622714 counting only the distinct ones).

The product of its digits is 11520, while the sum is 32.

The square root of 128512643 is about 11336.3416938623. The cubic root of 128512643 is about 504.6403255334.

The spelling of 128512643 in words is "one hundred twenty-eight million, five hundred twelve thousand, six hundred forty-three".