It is a happy number.
It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7421 = 41 ⋅181.
It is a cyclic number.
It is a Duffinian number.
It is a plaindrome in base 8, base 10 and base 16.
It is a nialpdrome in base 14.
It is a congruent number.
21247 is an apocalyptic number.
1247 is the 29-th pentagonal number.
1247 is an equidigital number, since it uses as much as digits as its factorization.
1247 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 72.
The square root of 1247 is about 35.3128871660. The cubic root of 1247 is about 10.7635488080.
Adding to 1247 its reverse (7421), we get a palindrome (8668).
The spelling of 1247 in words is "one thousand, two hundred forty-seven", and thus it is an iban number.