128256671 has 4 divisors (see below), whose sum is σ = 133833072. Its totient is φ = 122680272.

The previous prime is 128256649. The next prime is 128256673. The reversal of 128256671 is 176652821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 176652821 = 1019 ⋅173359.

It is a cyclic number.

It is not a de Polignac number, because 128256671 - 2¹⁸ = 127994527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128256673) 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, 2788166 + ... + 2788211.

It is an arithmetic number, because the mean of its divisors is an integer number (33458268).

Almost surely, 2^128256671 is an apocalyptic number.

128256671 is a deficient number, since it is larger than the sum of its proper divisors (5576401).

128256671 is an equidigital number, since it uses as much as digits as its factorization.

128256671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5576400.

The product of its digits is 40320, while the sum is 38.

The square root of 128256671 is about 11325.0461809213. The cubic root of 128256671 is about 504.3050546257.

The spelling of 128256671 in words is "one hundred twenty-eight million, two hundred fifty-six thousand, six hundred seventy-one".