128442647 has 4 divisors (see below), whose sum is σ = 129766896. Its totient is φ = 127118400.

The previous prime is 128442631. The next prime is 128442659. The reversal of 128442647 is 746244821.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 128442647 - 2⁴ = 128442631 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128442647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128442607) 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, 661979 + ... + 662172.

It is an arithmetic number, because the mean of its divisors is an integer number (32441724).

Almost surely, 2^128442647 is an apocalyptic number.

128442647 is a deficient number, since it is larger than the sum of its proper divisors (1324249).

128442647 is an equidigital number, since it uses as much as digits as its factorization.

128442647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1324248.

The product of its digits is 86016, while the sum is 38.

The square root of 128442647 is about 11333.2540340363. The cubic root of 128442647 is about 504.5486893635.

The spelling of 128442647 in words is "one hundred twenty-eight million, four hundred forty-two thousand, six hundred forty-seven".