1221210202021 has 16 divisors (see below), whose sum is σ = 1303842289600. Its totient is φ = 1140432110208.

The previous prime is 1221210202013. The next prime is 1221210202031. The reversal of 1221210202021 is 1202020121221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221210202021 - 2³ = 1221210202013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1221210201986 and 1221210202004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221210202001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2171095 + ... + 2675083.

It is an arithmetic number, because the mean of its divisors is an integer number (81490143100).

Almost surely, 2^{1221210202021} is an apocalyptic number.

It is an amenable number.

1221210202021 is a deficient number, since it is larger than the sum of its proper divisors (82632087579).

1221210202021 is a wasteful number, since it uses less digits than its factorization.

1221210202021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 505828.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 1221210202021 its reverse (1202020121221), we get a palindrome (2423230323242).

The spelling of 1221210202021 in words is "one trillion, two hundred twenty-one billion, two hundred ten million, two hundred two thousand, twenty-one".