128556663 has 8 divisors (see below), whose sum is σ = 171494400. Its totient is φ = 85661688.

The previous prime is 128556661. The next prime is 128556667. The reversal of 128556663 is 366655821.

It is a happy number.

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

It is not a de Polignac number, because 128556663 - 2¹ = 128556661 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128556661) 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, 2853 + ... + 16286.

It is an arithmetic number, because the mean of its divisors is an integer number (21436800).

Almost surely, 2^128556663 is an apocalyptic number.

128556663 is a deficient number, since it is larger than the sum of its proper divisors (42937737).

128556663 is a wasteful number, since it uses less digits than its factorization.

128556663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21381.

The product of its digits is 259200, while the sum is 42.

The square root of 128556663 is about 11338.2830710827. The cubic root of 128556663 is about 504.6979378448.

The spelling of 128556663 in words is "one hundred twenty-eight million, five hundred fifty-six thousand, six hundred sixty-three".