78912 has 42 divisors (see below), whose sum is σ = 227838. Its totient is φ = 26112.

The previous prime is 78901. The next prime is 78919. The reversal of 78912 is 21987.

It can be written as a sum of positive squares in only one way, i.e., 69696 + 9216 = 264^2 + 96^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78919) by changing a digit.

78912 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 508 + ... + 644.

2⁷⁸⁹¹² is an apocalyptic number.

78912 is a gapful number since it is divisible by the number (72) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (113919).

78912 is an abundant number, since it is smaller than the sum of its proper divisors (148926).

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

78912 is a wasteful number, since it uses less digits than its factorization.

78912 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 142 counting only the distinct ones).

The product of its digits is 1008, while the sum is 27.

The square root of 78912 is about 280.9127978573. The cubic root of 78912 is about 42.8924661163.

It can be divided in two parts, 78 and 912, that added together give a triangular number (990 = T₄₄).

The spelling of 78912 in words is "seventy-eight thousand, nine hundred twelve".