• 43 can be written using four 4's:
• Deleting all the even digits from 243 = 8796093022208 we obtain a prime (7993).
43 is nontrivially palindromic in base 6.
43 is an esthetic number in base 10 and base 13, because in such bases its adjacent digits differ by 1.
It is a weak prime.
43 is a truncatable prime.
It is a cyclic number.
It is the 7-th Jacobsthal number.
It is a magnanimous number.
It is a d-powerful number, because it can be written as 33 + 42 .
It is an alternating number because its digits alternate between even and odd.
It is the 7-th Hogben number.
43 is a lucky number.
43 is a nontrivial repdigit in base 6.
It is a plaindrome in base 4, base 5, base 6, base 9, base 11, base 12, base 13, base 15 and base 16.
It is a nialpdrome in base 6, base 7, base 8, base 10 and base 14.
It is a zygodrome in base 6.
It is a panconsummate number.
43 is the 4-th centered heptagonal number.
43 is an equidigital number, since it uses as much as digits as its factorization.
It is an anagram of its base 13 representation: 43 = (34)13.
43 is an evil number, because the sum of its binary digits is even.
The square root of 43 is about 6.5574385243. The cubic root of 43 is about 3.5033980604.
Adding to 43 its product of digits (12), we get a palindrome (55).
Adding to 43 its reverse (34), we get a palindrome (77).