128918789 has 6 divisors (see below), whose sum is σ = 129627666. Its totient is φ = 128213760.

The previous prime is 128918771. The next prime is 128918821. The reversal of 128918789 is 987819821.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 209764 + 128709025 = 458^2 + 11345^2 .

It is not a de Polignac number, because 128918789 - 2¹² = 128914693 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 128918789.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128915789) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 35519 + ... + 38979.

It is an arithmetic number, because the mean of its divisors is an integer number (21604611).

Almost surely, 2^128918789 is an apocalyptic number.

It is an amenable number.

128918789 is a deficient number, since it is larger than the sum of its proper divisors (708877).

128918789 is an frugal number, since it uses more digits than its factorization.

128918789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3847 (or 3654 counting only the distinct ones).

The product of its digits is 580608, while the sum is 53.

The square root of 128918789 is about 11354.2410138239. The cubic root of 128918789 is about 505.1713812333.

The spelling of 128918789 in words is "one hundred twenty-eight million, nine hundred eighteen thousand, seven hundred eighty-nine".