78428736 has 147 divisors (see below), whose sum is σ = 239171353. Its totient is φ = 25505280.

The previous prime is 78428719. The next prime is 78428741. The reversal of 78428736 is 63782487.

It is a happy number.

The square root of 78428736 is 8856.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 3779136 + 74649600 = 1944^2 + 8640^2 .

It is a Duffinian number.

Its product of digits (451584) is a multiple of the sum of its prime factors (112).

It is a junction number, because it is equal to n+sod(n) for n = 78428691 and 78428700.

It is an unprimeable number.

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 20 ways as a sum of consecutive naturals, for example, 1912876 + ... + 1912916.

Almost surely, 2^78428736 is an apocalyptic number.

78428736 is the 8856-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78428736

78428736 is an abundant number, since it is smaller than the sum of its proper divisors (160742617).

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

78428736 is an frugal number, since it uses more digits than its factorization.

78428736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112 (or 46 counting only the distinct ones).

The product of its digits is 451584, while the sum is 45.

The cubic root of 78428736 is about 428.0472769274.

Multiplying 78428736 by its product of digits (451584), we get a square (35417162317824 = 5951232²).

The spelling of 78428736 in words is "seventy-eight million, four hundred twenty-eight thousand, seven hundred thirty-six".