1213221221 has 8 divisors (see below), whose sum is σ = 1251216384. Its totient is φ = 1175670720.

The previous prime is 1213221203. The next prime is 1213221277. The reversal of 1213221221 is 1221223121.

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

It is a cyclic number.

It is not a de Polignac number, because 1213221221 - 2³⁰ = 139479397 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1213221221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1213221521) 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, 105620 + ... + 116541.

It is an arithmetic number, because the mean of its divisors is an integer number (156402048).

Almost surely, 2^1213221221 is an apocalyptic number.

It is an amenable number.

1213221221 is a deficient number, since it is larger than the sum of its proper divisors (37995163).

1213221221 is a wasteful number, since it uses less digits than its factorization.

1213221221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222331.

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

The square root of 1213221221 is about 34831.3252834284. The cubic root of 1213221221 is about 1066.5470022769.

Adding to 1213221221 its reverse (1221223121), we get a palindrome (2434444342).

The spelling of 1213221221 in words is "one billion, two hundred thirteen million, two hundred twenty-one thousand, two hundred twenty-one".