Adding to 421240 its reverse (42124), we get a palindrome (463364).
It is a self number, because there is not a number n which added to its sum of digits gives 421240.
It is a congruent number.
2421240 is an apocalyptic number.
421240 is a gapful number since it is divisible by the number (40) formed by its first and last digit.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
421240 is a wasteful number, since it uses less digits than its factorization.
421240 is an odious number, because the sum of its binary digits is odd.
The square root of 421240 is about 649.0300455295. The cubic root of 421240 is about 74.9623514747.
The spelling of 421240 in words is "four hundred twenty-one thousand, two hundred forty", and thus it is an iban number.