128891571 has 4 divisors (see below), whose sum is σ = 171855432. Its totient is φ = 85927712.

The previous prime is 128891557. The next prime is 128891591. The reversal of 128891571 is 175198821.

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 128891571 - 2⁶ = 128891507 is a prime.

It is a super-2 number, since 2×128891571² = 33226074149696082, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (128891551) 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, 21481926 + ... + 21481931.

It is an arithmetic number, because the mean of its divisors is an integer number (42963858).

Almost surely, 2^128891571 is an apocalyptic number.

128891571 is a deficient number, since it is larger than the sum of its proper divisors (42963861).

128891571 is an equidigital number, since it uses as much as digits as its factorization.

128891571 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42963860.

The product of its digits is 40320, while the sum is 42.

The square root of 128891571 is about 11353.0423675771. The cubic root of 128891571 is about 505.1358272682.

The spelling of 128891571 in words is "one hundred twenty-eight million, eight hundred ninety-one thousand, five hundred seventy-one".