128788669 has 4 divisors (see below), whose sum is σ = 135567040. Its totient is φ = 122010300.

The previous prime is 128788637. The next prime is 128788679. The reversal of 128788669 is 966887821.

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.

It is a cyclic number.

It is not a de Polignac number, because 128788669 - 2⁵ = 128788637 is a prime.

It is a super-2 number, since 2×128788669² = 33173042525583122, which 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 (128788619) 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, 3389157 + ... + 3389194.

It is an arithmetic number, because the mean of its divisors is an integer number (33891760).

Almost surely, 2^128788669 is an apocalyptic number.

128788669 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

128788669 is a deficient number, since it is larger than the sum of its proper divisors (6778371).

128788669 is an equidigital number, since it uses as much as digits as its factorization.

128788669 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6778370.

The product of its digits is 2322432, while the sum is 55.

The square root of 128788669 is about 11348.5095497162. The cubic root of 128788669 is about 505.0013645684.

The spelling of 128788669 in words is "one hundred twenty-eight million, seven hundred eighty-eight thousand, six hundred sixty-nine".