[go: up one dir, main page]
Search a number
tcefrep numbers
A number  $n$  is said to be tcefrep (which is perfect spelled backwards) if  $\sigma(n)$  is equal to  $n$  plus its reverse.

For example,  $498906$  is a tcefrep number since

\[\sigma(498906)=1108800=498906+609894.\]

The tcefrep numbers up to  $10^{13}$  are 6, 498906, 20671542, 41673714, 73687923, 4158499614, 922964834547.

Pictorial representation of remainders (mod 2, 3, ...,11) frequency. For a table of values and more details click here
remainders of tcefrep numbers
Useful links Joseph L. Pe, Tcefrep and Anti-Perfect Numbers
OEIS, Sequence A072234
Tcefrep numbers can also be... (you may click on names or numbers)

abundant 498906 20671542 41673714 arithmetic 498906 congruent 498906 Curzon 498906 evil 498906 20671542 interprime 41673714 odious 41673714 73687923 pseudoperfect 498906 wasteful 498906