1278781728 has 96 divisors (see below), whose sum is σ = 3858140160. Its totient is φ = 363290880.

The previous prime is 1278781727. The next prime is 1278781729. The reversal of 1278781728 is 8271878721.

It is an interprime number because it is at equal distance from previous prime (1278781727) and next prime (1278781729).

It is a tau number, because it is divible by the number of its divisors (96).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1278781723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 114973 + ... + 125603.

It is an arithmetic number, because the mean of its divisors is an integer number (40188960).

Almost surely, 2^1278781728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1278781728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1929070080).

1278781728 is an abundant number, since it is smaller than the sum of its proper divisors (2579358432).

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

1278781728 is a wasteful number, since it uses less digits than its factorization.

1278781728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10830 (or 10822 counting only the distinct ones).

The product of its digits is 702464, while the sum is 51.

The square root of 1278781728 is about 35760.0577180742. The cubic root of 1278781728 is about 1085.4224686510.

The spelling of 1278781728 in words is "one billion, two hundred seventy-eight million, seven hundred eighty-one thousand, seven hundred twenty-eight".