1221202021221 has 384 divisors, whose sum is σ = 2437972992000. Its totient is φ = 582814310400.

The previous prime is 1221202021201. The next prime is 1221202021271.

It is a happy number.

1221202021221 is a `hidden beast` number, since 1 + 221 + 20 + 202 + 1 + 221 = 666.

1221202021221 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1221202021221 - 2⁷ = 1221202021093 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221202021194 and 1221202021203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221202021201) by changing a digit.

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 383 ways as a sum of consecutive naturals, for example, 2549482060 + ... + 2549482538.

It is an arithmetic number, because the mean of its divisors is an integer number (6348888000).

Almost surely, 2^{1221202021221} is an apocalyptic number.

It is an amenable number.

1221202021221 is a deficient number, since it is larger than the sum of its proper divisors (1216770970779).

1221202021221 is a wasteful number, since it uses less digits than its factorization.

1221202021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 674 (or 657 counting only the distinct ones).

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

The spelling of 1221202021221 in words is "one trillion, two hundred twenty-one billion, two hundred two million, twenty-one thousand, two hundred twenty-one".