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12201221 = 16017621
BaseRepresentation
bin101110100010…
…110100000101
3211221212221002
4232202310011
511110414341
61113303045
7205465034
oct56426405
924855832
1012201221
116983a5a
124104a85
1326b2776
14189871b
15111029b
hexba2d05

12201221 has 4 divisors (see below), whose sum is σ = 12210444. Its totient is φ = 12192000.

The previous prime is 12201193. The next prime is 12201229. The reversal of 12201221 is 12210221.

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.

It can be written as a sum of positive squares in 2 ways, for example, as 11730625 + 470596 = 3425^2 + 686^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-12201221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12201229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2210 + ... + 5411.

It is an arithmetic number, because the mean of its divisors is an integer number (3052611).

Almost surely, 212201221 is an apocalyptic number.

It is an amenable number.

12201221 is a deficient number, since it is larger than the sum of its proper divisors (9223).

12201221 is an equidigital number, since it uses as much as digits as its factorization.

12201221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9222.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 12201221 is about 3493.0246205831. The cubic root of 12201221 is about 230.2154314217.

Adding to 12201221 its reverse (12210221), we get a palindrome (24411442).

The spelling of 12201221 in words is "twelve million, two hundred one thousand, two hundred twenty-one".

Divisors: 1 1601 7621 12201221