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RSA encryption/decryption. Are 8-letter blocks really needed?

The rsa code enciphering key is (n,e)=(8369428283,1234567). I found the deciphering key and deciphered the message AFTHVVNJARCSTZFZ (under the assumption that the plaintext consists of 7-letter blocks in the 26-letter alphabet, converted to an integer between 0 and 26^7-1 in the usual way, and the ciphertext consists of 8-letter blocks in the same alphabet).
The answer was CLAIMYOURPRIZE.

The question is: are 8-letter blocks for the ciphertext really needed? Either explain why not or give an example of a number whose encryption requires 8 positions.

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