85978 has 4 divisors (see below), whose sum is σ = 128970. Its totient is φ = 42988.

The previous prime is 85933. The next prime is 85991. The reversal of 85978 is 87958.

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

It can be written as a sum of positive squares in only one way, i.e., 74529 + 11449 = 273^2 + 107^2 .

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 as a sum of consecutive naturals, namely, 21493 + ... + 21496.

2⁸⁵⁹⁷⁸ is an apocalyptic number.

85978 is a deficient number, since it is larger than the sum of its proper divisors (42992).

85978 is a wasteful number, since it uses less digits than its factorization.

85978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42991.

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

The square root of 85978 is about 293.2200538845. The cubic root of 85978 is about 44.1362854232.

The spelling of 85978 in words is "eighty-five thousand, nine hundred seventy-eight".