78917 has 4 divisors (see below), whose sum is σ = 80460. Its totient is φ = 77376.

The previous prime is 78901. The next prime is 78919. The reversal of 78917 is 71987.

78917 is an esthetic number in base 11, because in such base its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 36481 + 42436 = 191^2 + 206^2 .

It is a cyclic number.

It is not a de Polignac number, because 78917 - 2⁴ = 78901 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78919) 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 in 3 ways as a sum of consecutive naturals, for example, 692 + ... + 797.

It is an arithmetic number, because the mean of its divisors is an integer number (20115).

2⁷⁸⁹¹⁷ is an apocalyptic number.

It is an amenable number.

78917 is a deficient number, since it is larger than the sum of its proper divisors (1543).

78917 is a wasteful number, since it uses less digits than its factorization.

78917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1542.

The product of its digits is 3528, while the sum is 32.

The square root of 78917 is about 280.9216972752. The cubic root of 78917 is about 42.8933720107.

The spelling of 78917 in words is "seventy-eight thousand, nine hundred seventeen".