42178 has 4 divisors (see below), whose sum is σ = 63270. Its totient is φ = 21088.

The previous prime is 42169. The next prime is 42179. The reversal of 42178 is 87124.

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., 23409 + 18769 = 153^2 + 137^2 .

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (42179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10543 + ... + 10546.

2⁴²¹⁷⁸ is an apocalyptic number.

42178 is a deficient number, since it is larger than the sum of its proper divisors (21092).

42178 is a wasteful number, since it uses less digits than its factorization.

42178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21091.

The product of its digits is 448, while the sum is 22.

The square root of 42178 is about 205.3728316988. The cubic root of 42178 is about 34.8093030133.

It can be divided in two parts, 4217 and 8, that added together give a square (4225 = 65²).

The spelling of 42178 in words is "forty-two thousand, one hundred seventy-eight".