1278745728 has 128 divisors (see below), whose sum is σ = 3688581120. Its totient is φ = 390168576.

The previous prime is 1278745723. The next prime is 1278745747. The reversal of 1278745728 is 8275478721.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (1278745723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 632976 + ... + 634992.

It is an arithmetic number, because the mean of its divisors is an integer number (28817040).

Almost surely, 2^1278745728 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 1278745728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1844290560).

1278745728 is an abundant number, since it is smaller than the sum of its proper divisors (2409835392).

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

1278745728 is a wasteful number, since it uses less digits than its factorization.

1278745728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2174 (or 2162 counting only the distinct ones).

The product of its digits is 1756160, while the sum is 51.

The square root of 1278745728 is about 35759.5543596393. The cubic root of 1278745728 is about 1085.4122830254.

The spelling of 1278745728 in words is "one billion, two hundred seventy-eight million, seven hundred forty-five thousand, seven hundred twenty-eight".