1221202021212 has 72 divisors (see below), whose sum is σ = 3152781712080. Its totient is φ = 398473240320.

The previous prime is 1221202021201. The next prime is 1221202021271. The reversal of 1221202021212 is 2121202021221.

It is a happy number.

It is a super-2 number, since 2×1221202021212² (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 congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1549089 + ... + 2200472.

It is an arithmetic number, because the mean of its divisors is an integer number (43788634890).

Almost surely, 2^{1221202021212} is an apocalyptic number.

1221202021212 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1221202021212 is an abundant number, since it is smaller than the sum of its proper divisors (1931579690868).

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

1221202021212 is a wasteful number, since it uses less digits than its factorization.

1221202021212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3749763 (or 3749758 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 18.

Adding to 1221202021212 its reverse (2121202021221), we get a palindrome (3342404042433).

Subtracting 1221202021212 from its reverse (2121202021221), we obtain a palindrome (900000000009).

The spelling of 1221202021212 in words is "one trillion, two hundred twenty-one billion, two hundred two million, twenty-one thousand, two hundred twelve".