1210221 has 20 divisors (see below), whose sum is σ = 1843072.
Its totient is φ = 791208.
The previous prime is 1210211. The next prime is 1210229. The reversal of 1210221 is 1220121.
1210221 = 1002 + 1012 + ... + 1662.
It is not a de Polignac number, because 1210221 - 27 = 1210093 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (1210229) by changing a digit.
It is a pernicious number, because its binary representation contains a prime number (13) of ones.
It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5316 + ... + 5538.
21210221 is an apocalyptic number.
It is an amenable number.
1210221 is a deficient number, since it is larger than the sum of its proper divisors (632851).
1210221 is an equidigital number, since it uses as much as digits as its factorization.
1210221 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 302 (or 293 counting only the distinct ones).
The product of its (nonzero) digits is 8, while the sum is 9.
The square root of 1210221 is about 1100.1004499590.
The cubic root of 1210221 is about 106.5667108325.
Adding to 1210221 its reverse (1220121), we get a palindrome (2430342).
It can be divided in two parts, 1210 and 221, that added together give a triangular number (1431 = T53).
The spelling of 1210221 in words is "one million, two hundred ten thousand, two hundred twenty-one".