78724 has 6 divisors (see below), whose sum is σ = 137774. Its totient is φ = 39360.

The previous prime is 78721. The next prime is 78737. The reversal of 78724 is 42787.

78724 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in only one way, i.e., 78400 + 324 = 280^2 + 18^2 .

It is a junction number, because it is equal to n+sod(n) for n = 78692 and 78701.

It is not an unprimeable number, because it can be changed into a prime (78721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9837 + ... + 9844.

2⁷⁸⁷²⁴ is an apocalyptic number.

It is an amenable number.

78724 is a deficient number, since it is larger than the sum of its proper divisors (59050).

78724 is a wasteful number, since it uses less digits than its factorization.

78724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19685 (or 19683 counting only the distinct ones).

The product of its digits is 3136, while the sum is 28.

The square root of 78724 is about 280.5779749018. The cubic root of 78724 is about 42.8583766841.

Subtracting from 78724 its reverse (42787), we obtain a cube (35937 = 33³).

The spelling of 78724 in words is "seventy-eight thousand, seven hundred twenty-four".