1280000128 has 32 divisors (see below), whose sum is σ = 2781821520. Its totient is φ = 581817600.

The previous prime is 1280000101. The next prime is 1280000129. The reversal of 1280000128 is 8210000821.

It is a tau number, because it is divible by the number of its divisors (32).

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 1280000099 and 1280000108.

It is not an unprimeable number, because it can be changed into a prime (1280000129) 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, 453138 + ... + 455953.

Almost surely, 2^1280000128 is an apocalyptic number.

It is an amenable number.

1280000128 is an abundant number, since it is smaller than the sum of its proper divisors (1501821392).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1280000128 is an equidigital number, since it uses as much as digits as its factorization.

1280000128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 909116 (or 909104 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 1280000128 is about 35777.0894288510. The cubic root of 1280000128 is about 1085.7670828302.

Adding to 1280000128 its reverse (8210000821), we get a palindrome (9490000949).

It can be divided in two parts, 1280000 and 128, that multiplied together give a square (163840000 = 12800²).

The spelling of 1280000128 in words is "one billion, two hundred eighty million, one hundred twenty-eight", and thus it is an aban number.