1213021312 has 48 divisors (see below), whose sum is σ = 2443356450. Its totient is φ = 599859200.

The previous prime is 1213021301. The next prime is 1213021319. The reversal of 1213021312 is 2131203121.

It can be written as a sum of positive squares in 3 ways, for example, as 1192735296 + 20286016 = 34536^2 + 4504^2 .

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 (1213021319) 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 5 ways as a sum of consecutive naturals, for example, 1305264 + ... + 1306192.

Almost surely, 2^1213021312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1213021312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1221678225).

1213021312 is an abundant number, since it is smaller than the sum of its proper divisors (1230335138).

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

1213021312 is an frugal number, since it uses more digits than its factorization.

1213021312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145 (or 1032 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 1213021312 is about 34828.4554925997. The cubic root of 1213021312 is about 1066.4884188262.

Adding to 1213021312 its reverse (2131203121), we get a palindrome (3344224433).

The spelling of 1213021312 in words is "one billion, two hundred thirteen million, twenty-one thousand, three hundred twelve".