1221121111212 has 72 divisors (see below), whose sum is σ = 3179129562336. Its totient is φ = 394917202944.

The previous prime is 1221121111193. The next prime is 1221121111213. The reversal of 1221121111212 is 2121111211221.

It is a happy number.

1221121111212 is a `hidden beast` number, since 1 + 221 + 121 + 111 + 212 = 666.

It is a super-2 number, since 2×1221121111212² (a number of 25 digits) contains 22 as substring.

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 (1221121111213) 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, 828328 + ... + 1768719.

Almost surely, 2^{1221121111212} is an apocalyptic number.

1221121111212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221121111212 is an abundant number, since it is smaller than the sum of its proper divisors (1958008451124).

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

1221121111212 is a wasteful number, since it uses less digits than its factorization.

1221121111212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2597447 (or 2597442 counting only the distinct ones).

The product of its digits is 32, while the sum is 18.

Adding to 1221121111212 its reverse (2121111211221), we get a palindrome (3342232322433).

The spelling of 1221121111212 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twelve".