1212220221 has 8 divisors (see below), whose sum is σ = 1686567360. Its totient is φ = 773009952.

The previous prime is 1212220211. The next prime is 1212220223. The reversal of 1212220221 is 1220222121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1212220221 - 2¹⁵ = 1212187453 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1212220221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212220223) 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 7 ways as a sum of consecutive naturals, for example, 8784136 + ... + 8784273.

It is an arithmetic number, because the mean of its divisors is an integer number (210820920).

Almost surely, 2^1212220221 is an apocalyptic number.

It is an amenable number.

1212220221 is a deficient number, since it is larger than the sum of its proper divisors (474347139).

1212220221 is a wasteful number, since it uses less digits than its factorization.

1212220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17568435.

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 1212220221 is about 34816.9530688715. The cubic root of 1212220221 is about 1066.2535940382.

Adding to 1212220221 its reverse (1220222121), we get a palindrome (2432442342).

The spelling of 1212220221 in words is "one billion, two hundred twelve million, two hundred twenty thousand, two hundred twenty-one".