1221304212 has 72 divisors (see below), whose sum is σ = 3162047616. Its totient is φ = 397281024.

The previous prime is 1221304171. The next prime is 1221304219. The reversal of 1221304212 is 2124031221.

It is a happy number.

1221304212 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×1221304212³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221304219) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 731803 + ... + 733469.

It is an arithmetic number, because the mean of its divisors is an integer number (43917328).

Almost surely, 2^1221304212 is an apocalyptic number.

1221304212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1221304212, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1581023808).

1221304212 is an abundant number, since it is smaller than the sum of its proper divisors (1940743404).

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

1221304212 is a wasteful number, since it uses less digits than its factorization.

1221304212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2157 (or 2152 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 1221304212 is about 34947.1631466704. The cubic root of 1221304212 is about 1068.9103566507.

Adding to 1221304212 its reverse (2124031221), we get a palindrome (3345335433).

The spelling of 1221304212 in words is "one billion, two hundred twenty-one million, three hundred four thousand, two hundred twelve".