78428224 has 84 divisors (see below), whose sum is σ = 183725820. Its totient is φ = 33116160.

The previous prime is 78428201. The next prime is 78428237. The reversal of 78428224 is 42282487.

78428224 = 127³ + 128³ + ... + 154³.

It can be written as a sum of positive squares in 2 ways, for example, as 33269824 + 45158400 = 5768^2 + 6720^2 .

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 278964 + ... + 279244.

Almost surely, 2^78428224 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 78428224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91862910).

78428224 is an abundant number, since it is smaller than the sum of its proper divisors (105297596).

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

78428224 is a wasteful number, since it uses less digits than its factorization.

78428224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 396 (or 379 counting only the distinct ones).

The product of its digits is 57344, while the sum is 37.

The square root of 78428224 is about 8855.9710929971. The cubic root of 78428224 is about 428.0463454632.

It can be divided in two parts, 784 and 28224, that multiplied together give a square (22127616 = 4704²).

The spelling of 78428224 in words is "seventy-eight million, four hundred twenty-eight thousand, two hundred twenty-four".