128585491 has 4 divisors (see below), whose sum is σ = 129355632. Its totient is φ = 127815352.

The previous prime is 128585461. The next prime is 128585503. The reversal of 128585491 is 194585821.

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 128585491 - 2⁷ = 128585363 is a prime.

It is a super-2 number, since 2×128585491² = 33068456991422162, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128585461) 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, 384820 + ... + 385153.

It is an arithmetic number, because the mean of its divisors is an integer number (32338908).

Almost surely, 2^128585491 is an apocalyptic number.

128585491 is a deficient number, since it is larger than the sum of its proper divisors (770141).

128585491 is an equidigital number, since it uses as much as digits as its factorization.

128585491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 770140.

The product of its digits is 115200, while the sum is 43.

The square root of 128585491 is about 11339.5542681359. The cubic root of 128585491 is about 504.7356601078.

The spelling of 128585491 in words is "one hundred twenty-eight million, five hundred eighty-five thousand, four hundred ninety-one".