• 178 can be written using four 4's:

See also 113.

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178 has 4 divisors (see below), whose sum is σ = 270. Its totient is φ = 88.

The previous prime is 173. The next prime is 179. The reversal of 178 is 871.

178 is nontrivially palindromic in base 6, base 7 and base 8.

178 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

178 is an esthetic number in base 6 and base 7, because in such bases its adjacent digits differ by 1.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 871 = 13 ⋅67.

It can be written as a sum of positive squares in only one way, i.e., 169 + 9 = 13^2 + 3^2 .

178 is an undulating number in base 6, base 7 and base 8.

It is a plaindrome in base 10, base 12 and base 15.

It is a nialpdrome in base 14 and base 16.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43 + ... + 46.

178 is a deficient number, since it is larger than the sum of its proper divisors (92).

178 is an equidigital number, since it uses as much as digits as its factorization.

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

The sum of its prime factors is 91.

The product of its digits is 56, while the sum is 16.

The square root of 178 is about 13.3416640641. The cubic root of 178 is about 5.6252263283.

It can be divided in two parts, 17 and 8, that multiplied together give a triangular number (136 = T₁₆).

The spelling of 178 in words is "one hundred seventy-eight", and thus it is an aban number.