128663641 has 4 divisors (see below), whose sum is σ = 129240832. Its totient is φ = 128086452.

The previous prime is 128663621. The next prime is 128663653. The reversal of 128663641 is 146366821.

It is a happy number.

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: 146366821 = 17 ⋅8609813.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128663641 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128663641.

It is not an unprimeable number, because it can be changed into a prime (128663621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 288261 + ... + 288706.

It is an arithmetic number, because the mean of its divisors is an integer number (32310208).

Almost surely, 2^128663641 is an apocalyptic number.

It is an amenable number.

128663641 is a deficient number, since it is larger than the sum of its proper divisors (577191).

128663641 is an equidigital number, since it uses as much as digits as its factorization.

128663641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 577190.

The product of its digits is 41472, while the sum is 37.

The square root of 128663641 is about 11342.9996473596. Note that the first 3 decimals coincide. The cubic root of 128663641 is about 504.8378932682.

The spelling of 128663641 in words is "one hundred twenty-eight million, six hundred sixty-three thousand, six hundred forty-one".