10211221 has 2 divisors, whose sum is σ = 10211222.
Its totient is φ = 10211220.
The previous prime is 10211213. The next prime is 10211239. The reversal of 10211221 is 12211201.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 9678321 + 532900 = 3111^2 + 730^2
It is a cyclic number.
It is not a de Polignac number, because 10211221 - 23 = 10211213 is a prime.
It is the 3196-th Hogben number.
It is a junction number, because it is equal to n+sod(n) for n = 10211198 and 10211207.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (10211251) by changing a digit.
It is a nontrivial repunit in base 3195.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5105610 + 5105611.
It is an arithmetic number, because the mean of its divisors is an integer number (5105611).
Almost surely, 210211221 is an apocalyptic number.
It is an amenable number.
10211221 is a deficient number, since it is larger than the sum of its proper divisors (1).
10211221 is an equidigital number, since it uses as much as digits as its factorization.
10211221 is an odious number, because the sum of its binary digits is odd.
The product of its (nonzero) digits is 8, while the sum is 10.
The square root of 10211221 is about 3195.5001173525.
The cubic root of 10211221 is about 216.9497855737.
Adding to 10211221 its reverse (12211201), we get a palindrome (22422422).
The spelling of 10211221 in words is "ten million, two hundred eleven thousand, two hundred twenty-one".