78424820 has 24 divisors (see below), whose sum is σ = 164921064. Its totient is φ = 31326336.

The previous prime is 78424817. The next prime is 78424831. The reversal of 78424820 is 2842487.

It can be written as a sum of positive squares in 4 ways, for example, as 3290596 + 75134224 = 1814^2 + 8668^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14762 + ... + 19358.

It is an arithmetic number, because the mean of its divisors is an integer number (6871711).

Almost surely, 2^78424820 is an apocalyptic number.

It is an amenable number.

78424820 is an abundant number, since it is smaller than the sum of its proper divisors (86496244).

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

78424820 is a wasteful number, since it uses less digits than its factorization.

78424820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5459 (or 5457 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 35.

The square root of 78424820 is about 8855.7789041958. The cubic root of 78424820 is about 428.0401525785.

The spelling of 78424820 in words is "seventy-eight million, four hundred twenty-four thousand, eight hundred twenty".