128405557 has 8 divisors (see below), whose sum is σ = 147071232. Its totient is φ = 109820400.

The previous prime is 128405521. The next prime is 128405569. The reversal of 128405557 is 755504821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 128405557 - 2¹⁵ = 128372789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128405507) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16669 + ... + 23122.

It is an arithmetic number, because the mean of its divisors is an integer number (18383904).

Almost surely, 2^128405557 is an apocalyptic number.

It is an amenable number.

128405557 is a deficient number, since it is larger than the sum of its proper divisors (18665675).

128405557 is an equidigital number, since it uses as much as digits as its factorization.

128405557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40259.

The product of its (nonzero) digits is 56000, while the sum is 37.

The square root of 128405557 is about 11331.6175809105. The cubic root of 128405557 is about 504.5001190147.

The spelling of 128405557 in words is "one hundred twenty-eight million, four hundred five thousand, five hundred fifty-seven".