1212543221 has 2 divisors, whose sum is σ = 1212543222. Its totient is φ = 1212543220.

The previous prime is 1212543217. The next prime is 1212543229. The reversal of 1212543221 is 1223452121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 980316100 + 232227121 = 31310^2 + 15239^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212543221 - 2² = 1212543217 is a prime.

It is a super-2 number, since 2×1212543221² = 2940522125586109682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212543229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606271610 + 606271611.

It is an arithmetic number, because the mean of its divisors is an integer number (606271611).

Almost surely, 2^1212543221 is an apocalyptic number.

It is an amenable number.

1212543221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212543221 is an equidigital number, since it uses as much as digits as its factorization.

1212543221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 23.

The square root of 1212543221 is about 34821.5913048212. The cubic root of 1212543221 is about 1066.3482878682.

Adding to 1212543221 its reverse (1223452121), we get a palindrome (2435995342).

The spelling of 1212543221 in words is "one billion, two hundred twelve million, five hundred forty-three thousand, two hundred twenty-one".