128228605669 has 4 divisors (see below), whose sum is σ = 135771464844. Its totient is φ = 120685746496.

The previous prime is 128228605663. The next prime is 128228605679. The reversal of 128228605669 is 966506822821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 966506822821 = 541 ⋅1786519081.

It can be written as a sum of positive squares in 2 ways, for example, as 59131648900 + 69096956769 = 243170^2 + 262863^2 .

It is a cyclic number.

It is not a de Polignac number, because 128228605669 - 2¹¹ = 128228603621 is a prime.

It is a super-2 number, since 2×128228605669² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128228605663) 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, 3771429562 + ... + 3771429595.

It is an arithmetic number, because the mean of its divisors is an integer number (33942866211).

Almost surely, 2^128228605669 is an apocalyptic number.

It is an amenable number.

128228605669 is a deficient number, since it is larger than the sum of its proper divisors (7542859175).

128228605669 is an equidigital number, since it uses as much as digits as its factorization.

128228605669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7542859174.

The product of its (nonzero) digits is 4976640, while the sum is 55.

The spelling of 128228605669 in words is "one hundred twenty-eight billion, two hundred twenty-eight million, six hundred five thousand, six hundred sixty-nine".