A number series is given below, in which only one number is wrong. Find out the wrong number. 1321, 1537, 2049, 2778, 4777, 7521, 11617

Analyze the differences between the consecutive terms: 216, 512, 729, 1999, 2744, and 4096. Notice that 512 is 8 cubed, 729 is 9 cubed, and 4096 is 16 cubed. The expected differences should be cubes of consecutive integers: 11 cubed is 1331 (1321 + 1331 = 2652), which breaks the simple cube pattern. Instead, the differences are based on prime numbers multiplied by squares or other specific logic, but 2778 is the clear outlier because 2049 + 13 cubed (2197) equals 4246, making 2778 disrupt the sequence. The result is 2778.

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