128555601 has 4 divisors (see below), whose sum is σ = 171407472. Its totient is φ = 85703732.

The previous prime is 128555599. The next prime is 128555617. The reversal of 128555601 is 106555821.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 106555821 = 3 ⋅35518607.

It is a cyclic number.

It is not a de Polignac number, because 128555601 - 2¹ = 128555599 is a prime.

It is not an unprimeable number, because it can be changed into a prime (128555621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21425931 + ... + 21425936.

It is an arithmetic number, because the mean of its divisors is an integer number (42851868).

Almost surely, 2^128555601 is an apocalyptic number.

It is an amenable number.

128555601 is a deficient number, since it is larger than the sum of its proper divisors (42851871).

128555601 is an equidigital number, since it uses as much as digits as its factorization.

128555601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42851870.

The product of its (nonzero) digits is 12000, while the sum is 33.

The square root of 128555601 is about 11338.2362384985. The cubic root of 128555601 is about 504.6965480797.

The spelling of 128555601 in words is "one hundred twenty-eight million, five hundred fifty-five thousand, six hundred one".