42978 has 32 divisors (see below), whose sum is σ = 100800. Its totient is φ = 12096.

The previous prime is 42967. The next prime is 42979. The reversal of 42978 is 87924.

It is a Smith number, since the sum of its digits (30) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 42978.

It is not an unprimeable number, because it can be changed into a prime (42979) by changing a digit.

42978 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1468 + ... + 1496.

It is an arithmetic number, because the mean of its divisors is an integer number (3150).

2⁴²⁹⁷⁸ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 42978, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50400).

42978 is an abundant number, since it is smaller than the sum of its proper divisors (57822).

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

42978 is a wasteful number, since it uses less digits than its factorization.

42978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66.

The product of its digits is 4032, while the sum is 30.

The square root of 42978 is about 207.3113600361. The cubic root of 42978 is about 35.0280047972.

The spelling of 42978 in words is "forty-two thousand, nine hundred seventy-eight".