# 170 (number)

170 is the natural number following 169 and preceding 171.

 Template:Numbers 100-200 Ordinal One hundred [and] seventy Cardinal 170th Factorization [itex] 2 \cdot 5 \cdot 17[itex] Roman numeral CLXX Binary 10101010 Hexadecimal AA

One hundred seventy a sphenic number. It is the smallest n for which φ(n) and σ(n) are both square. But 170 is never a solution for φ(x), making it a nontotient. Nor is it ever a solution to x - φ(x), making it a noncototient.

One hundred seventy is also

## Numbers in the 170s

171 = 3^2 19, triangular number, Harshad number

172 = 2^2 43, noncototient

173 = prime number, Sophie Germain prime, sum of three consecutive primes (53 + 59 + 61)

174 = 2 3 29, sphenic number, nontotient

175 = 5^2 7

177 = 3 59

178 = 2 89

179 = prime number, Sophie Germain prime, safe prime, strictly non-palindromic number

ko:170

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