1221020111211 has 16 divisors (see below), whose sum is σ = 1629587731968. Its totient is φ = 813233108000.

The previous prime is 1221020111173. The next prime is 1221020111237. The reversal of 1221020111211 is 1121110201221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221020111211 - 2⁷ = 1221020111083 is a prime.

It is a super-2 number, since 2×1221020111211² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1221020191211) 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 15 ways as a sum of consecutive naturals, for example, 49770430 + ... + 49794956.

It is an arithmetic number, because the mean of its divisors is an integer number (101849233248).

Almost surely, 2^{1221020111211} is an apocalyptic number.

1221020111211 is a deficient number, since it is larger than the sum of its proper divisors (408567620757).

1221020111211 is a wasteful number, since it uses less digits than its factorization.

1221020111211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39762.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 1221020111211 its reverse (1121110201221), we get a palindrome (2342130312432).

The spelling of 1221020111211 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred eleven thousand, two hundred eleven".