78815538 has 64 divisors (see below), whose sum is σ = 181059840. Its totient is φ = 25401600.

The previous prime is 78815501. The next prime is 78815543. The reversal of 78815538 is 83551887.

It is a happy number.

Its product of digits (268800) is a multiple of the sum of its prime factors (480).

It is a junction number, because it is equal to n+sod(n) for n = 78815493 and 78815502.

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 31 ways as a sum of consecutive naturals, for example, 233706 + ... + 234042.

It is an arithmetic number, because the mean of its divisors is an integer number (2829060).

Almost surely, 2^78815538 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78815538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90529920).

78815538 is an abundant number, since it is smaller than the sum of its proper divisors (102244302).

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

78815538 is a wasteful number, since it uses less digits than its factorization.

78815538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480 (or 474 counting only the distinct ones).

The product of its digits is 268800, while the sum is 45.

The square root of 78815538 is about 8877.8115546569. The cubic root of 78815538 is about 428.7498174513.

The spelling of 78815538 in words is "seventy-eight million, eight hundred fifteen thousand, five hundred thirty-eight".