1221212213 has 16 divisors (see below), whose sum is σ = 1385939520. Its totient is φ = 1066732416.

The previous prime is 1221212191. The next prime is 1221212219. The reversal of 1221212213 is 3122121221.

It is a cyclic number.

It is not a de Polignac number, because 1221212213 - 2¹⁸ = 1220950069 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221212191 and 1221212200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221212219) 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 15 ways as a sum of consecutive naturals, for example, 268706 + ... + 273212.

It is an arithmetic number, because the mean of its divisors is an integer number (86621220).

Almost surely, 2^1221212213 is an apocalyptic number.

1221212213 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1221212213 is a deficient number, since it is larger than the sum of its proper divisors (164727307).

1221212213 is a wasteful number, since it uses less digits than its factorization.

1221212213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5636.

The product of its digits is 96, while the sum is 17.

The square root of 1221212213 is about 34945.8468633971. The cubic root of 1221212213 is about 1068.8835161763.

Adding to 1221212213 its reverse (3122121221), we get a palindrome (4343333434).

It can be divided in two parts, 122121221 and 3, that multiplied together give a palindrome (366363663).

The spelling of 1221212213 in words is "one billion, two hundred twenty-one million, two hundred twelve thousand, two hundred thirteen".