It is a semiprime because it is the product of two primes.
It is a congruent number.
It is an unprimeable number.
21531646 is an apocalyptic number.
1531646 is an equidigital number, since it uses as much as digits as its factorization.
1531646 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 765825.
The square root of 1531646 is about 1237.5968648958. The cubic root of 1531646 is about 115.2708424057.
Adding to 1531646 its reverse (6461351), we get a palindrome (7992997).
The spelling of 1531646 in words is "one million, five hundred thirty-one thousand, six hundred forty-six".