128185831 has 16 divisors (see below), whose sum is σ = 142720704. Its totient is φ = 114509824.

The previous prime is 128185823. The next prime is 128185847. The reversal of 128185831 is 138581821.

It is not a de Polignac number, because 128185831 - 2³ = 128185823 is a prime.

It is a super-2 number, since 2×128185831² = 32863214538321122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128185891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52371 + ... + 54763.

It is an arithmetic number, because the mean of its divisors is an integer number (8920044).

Almost surely, 2^128185831 is an apocalyptic number.

128185831 is a deficient number, since it is larger than the sum of its proper divisors (14534873).

128185831 is a wasteful number, since it uses less digits than its factorization.

128185831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2570.

The product of its digits is 15360, while the sum is 37.

The square root of 128185831 is about 11321.9181678724. The cubic root of 128185831 is about 504.2121899320.

The spelling of 128185831 in words is "one hundred twenty-eight million, one hundred eighty-five thousand, eight hundred thirty-one".