778128 has 80 divisors (see below), whose sum is σ = 2291520. Its totient is φ = 225792.

The previous prime is 778123. The next prime is 778153. The reversal of 778128 is 821877.

778128 is a nontrivial binomial coefficient, being equal to C(1248, 2).

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (778121) 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, 18075 + ... + 18117.

It is an arithmetic number, because the mean of its divisors is an integer number (28644).

2⁷⁷⁸¹²⁸ is an apocalyptic number.

778128 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

778128 is the 1247-th triangular number and also the 624-th hexagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 778128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1145760).

778128 is an abundant number, since it is smaller than the sum of its proper divisors (1513392).

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

778128 is a wasteful number, since it uses less digits than its factorization.

778128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96 (or 90 counting only the distinct ones).

The product of its digits is 6272, while the sum is 33.

The square root of 778128 is about 882.1156386778. The cubic root of 778128 is about 91.9779405208.

The spelling of 778128 in words is "seven hundred seventy-eight thousand, one hundred twenty-eight".