128531557 has 12 divisors (see below), whose sum is σ = 163109376. Its totient is φ = 100154040.

The previous prime is 128531551. The next prime is 128531563. The reversal of 128531557 is 755135821.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (128531551) and next prime (128531563).

It is a de Polignac number, because none of the positive numbers 2^k-128531557 is a prime.

It is a super-2 number, since 2×128531557² = 33040722289688498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128531551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 118693 + ... + 119770.

It is an arithmetic number, because the mean of its divisors is an integer number (13592448).

Almost surely, 2^128531557 is an apocalyptic number.

It is an amenable number.

128531557 is a deficient number, since it is larger than the sum of its proper divisors (34577819).

128531557 is a wasteful number, since it uses less digits than its factorization.

128531557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238488 (or 238481 counting only the distinct ones).

The product of its digits is 42000, while the sum is 37.

The square root of 128531557 is about 11337.1758829084. The cubic root of 128531557 is about 504.6650813309.

The spelling of 128531557 in words is "one hundred twenty-eight million, five hundred thirty-one thousand, five hundred fifty-seven".