128172557 has 6 divisors (see below), whose sum is σ = 128697642. Its totient is φ = 127649552.

The previous prime is 128172533. The next prime is 128172559. The reversal of 128172557 is 755271821.

It can be written as a sum of positive squares in 3 ways, for example, as 107205316 + 20967241 = 10354^2 + 4579^2 .

It is not a de Polignac number, because 128172557 - 2⁸ = 128172301 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 128172557.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128172559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 85103 + ... + 86595.

It is an arithmetic number, because the mean of its divisors is an integer number (21449607).

Almost surely, 2^128172557 is an apocalyptic number.

It is an amenable number.

128172557 is a deficient number, since it is larger than the sum of its proper divisors (525085).

128172557 is an frugal number, since it uses more digits than its factorization.

128172557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2079 (or 1786 counting only the distinct ones).

The product of its digits is 39200, while the sum is 38.

The square root of 128172557 is about 11321.3319446079. The cubic root of 128172557 is about 504.1947851388.

The spelling of 128172557 in words is "one hundred twenty-eight million, one hundred seventy-two thousand, five hundred fifty-seven".