1221331212 has 18 divisors (see below), whose sum is σ = 3087253988. Its totient is φ = 407110392.

The previous prime is 1221331117. The next prime is 1221331219. The reversal of 1221331212 is 2121331221.

1221331212 is a `hidden beast` number, since 122 + 1 + 331 + 212 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

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

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (1221331219) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 16962898 + ... + 16962969.

Almost surely, 2^1221331212 is an apocalyptic number.

1221331212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221331212 is an abundant number, since it is smaller than the sum of its proper divisors (1865922776).

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

1221331212 is a wasteful number, since it uses less digits than its factorization.

1221331212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33925877 (or 33925872 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 1221331212 is about 34947.5494419852. The cubic root of 1221331212 is about 1068.9182335762.

Adding to 1221331212 its reverse (2121331221), we get a palindrome (3342662433).

Subtracting 1221331212 from its reverse (2121331221), we obtain a palindrome (900000009).

The spelling of 1221331212 in words is "one billion, two hundred twenty-one million, three hundred thirty-one thousand, two hundred twelve".