1221020121011 has 4 divisors (see below), whose sum is σ = 1228797319392. Its totient is φ = 1213242922632.

The previous prime is 1221020120993. The next prime is 1221020121047. The reversal of 1221020121011 is 1101210201221.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221020121011 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221020121611) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3888598955 + ... + 3888599268.

It is an arithmetic number, because the mean of its divisors is an integer number (307199329848).

Almost surely, 2^{1221020121011} is an apocalyptic number.

1221020121011 is a deficient number, since it is larger than the sum of its proper divisors (7777198381).

1221020121011 is an equidigital number, since it uses as much as digits as its factorization.

1221020121011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7777198380.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 1221020121011 its reverse (1101210201221), we get a palindrome (2322230322232).

It can be divided in two parts, 12210201210 and 11, that added together give a palindrome (12210201221).

The spelling of 1221020121011 in words is "one trillion, two hundred twenty-one billion, twenty million, one hundred twenty-one thousand, eleven".