1221020111221 has 8 divisors (see below), whose sum is σ = 1232798978840. Its totient is φ = 1209251731968.

The previous prime is 1221020111173. The next prime is 1221020111237. The reversal of 1221020111221 is 1221110201221.

It can be written as a sum of positive squares in 4 ways, for example, as 313880062500 + 907140048721 = 560250^2 + 952439^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221020111221 - 2⁷ = 1221020111093 is a prime.

It is a super-2 number, since 2×1221020111221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1221020111195 and 1221020111204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221020111821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2388036 + ... + 2853901.

It is an arithmetic number, because the mean of its divisors is an integer number (154099872355).

Almost surely, 2^{1221020111221} is an apocalyptic number.

It is an amenable number.

1221020111221 is a deficient number, since it is larger than the sum of its proper divisors (11778867619).

1221020111221 is a wasteful number, since it uses less digits than its factorization.

1221020111221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5244183.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 1221020111221 its reverse (1221110201221), we get a palindrome (2442130312442).

The spelling of 1221020111221 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred eleven thousand, two hundred twenty-one".