128581605 has 12 divisors (see below), whose sum is σ = 222874860. Its totient is φ = 68576832.

The previous prime is 128581603. The next prime is 128581627. The reversal of 128581605 is 506185821.

128581605 is a `hidden beast` number, since 12 + 8 + 581 + 60 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 90611361 + 37970244 = 9519^2 + 6162^2 .

It is not a de Polignac number, because 128581605 - 2¹ = 128581603 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128581605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128581601) 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, 1428640 + ... + 1428729.

It is an arithmetic number, because the mean of its divisors is an integer number (18572905).

Almost surely, 2^128581605 is an apocalyptic number.

128581605 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

128581605 is a deficient number, since it is larger than the sum of its proper divisors (94293255).

128581605 is a wasteful number, since it uses less digits than its factorization.

128581605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2857380 (or 2857377 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 36.

The square root of 128581605 is about 11339.3829197183. The cubic root of 128581605 is about 504.7305754944.

The spelling of 128581605 in words is "one hundred twenty-eight million, five hundred eighty-one thousand, six hundred five".