78985 has 4 divisors (see below), whose sum is σ = 94788. Its totient is φ = 63184.

The previous prime is 78979. The next prime is 78989. The reversal of 78985 is 58987.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58987 = 61 ⋅967.

It can be written as a sum of positive squares in 2 ways, for example, as 43264 + 35721 = 208^2 + 189^2 .

It is a cyclic number.

It is not a de Polignac number, because 78985 - 2³ = 78977 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

78985 is a lucky number.

It is a plaindrome in base 16.

It is not an unprimeable number, because it can be changed into a prime (78989) 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, 7894 + ... + 7903.

It is an arithmetic number, because the mean of its divisors is an integer number (23697).

2⁷⁸⁹⁸⁵ is an apocalyptic number.

It is an amenable number.

78985 is a deficient number, since it is larger than the sum of its proper divisors (15803).

78985 is a wasteful number, since it uses less digits than its factorization.

78985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15802.

The product of its digits is 20160, while the sum is 37.

The square root of 78985 is about 281.0427013818. The cubic root of 78985 is about 42.9056883766.

The spelling of 78985 in words is "seventy-eight thousand, nine hundred eighty-five".