1211221202021 has 16 divisors (see below), whose sum is σ = 1227100492800. Its totient is φ = 1195394057088.

The previous prime is 1211221202011. The next prime is 1211221202027. The reversal of 1211221202021 is 1202021221121.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1211221202021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211221202027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 217334591 + ... + 217340163.

It is an arithmetic number, because the mean of its divisors is an integer number (76693780800).

Almost surely, 2^{1211221202021} is an apocalyptic number.

It is an amenable number.

1211221202021 is a deficient number, since it is larger than the sum of its proper divisors (15879290779).

1211221202021 is an equidigital number, since it uses as much as digits as its factorization.

1211221202021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9748.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 1211221202021 its reverse (1202021221121), we get a palindrome (2413242423142).

The spelling of 1211221202021 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred two thousand, twenty-one".