1211221312 has 28 divisors (see below), whose sum is σ = 2746877920. Its totient is φ = 519094656.

The previous prime is 1211221309. The next prime is 1211221313. The reversal of 1211221312 is 2131221121.

It is a tau number, because it is divible by the number of its divisors (28).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211221313) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1351362 + ... + 1352257.

Almost surely, 2^1211221312 is an apocalyptic number.

It is an amenable number.

1211221312 is an abundant number, since it is smaller than the sum of its proper divisors (1535656608).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211221312 is an equidigital number, since it uses as much as digits as its factorization.

1211221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2703638 (or 2703628 counting only the distinct ones).

The product of its digits is 48, while the sum is 16.

The square root of 1211221312 is about 34802.6049599739. The cubic root of 1211221312 is about 1065.9606376420.

Adding to 1211221312 its reverse (2131221121), we get a palindrome (3342442433).

The spelling of 1211221312 in words is "one billion, two hundred eleven million, two hundred twenty-one thousand, three hundred twelve".