1221211122021 has 24 divisors (see below), whose sum is σ = 1940236272000. Its totient is φ = 740127945480.

The previous prime is 1221211121989. The next prime is 1221211122049. The reversal of 1221211122021 is 1202211121221.

It is not a de Polignac number, because 1221211122021 - 2⁵ = 1221211121989 is a prime.

It is a super-2 number, since 2×1221211122021² (a number of 25 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1221211121985 and 1221211122003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221211122421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 50961021 + ... + 50984978.

It is an arithmetic number, because the mean of its divisors is an integer number (80843178000).

Almost surely, 2^{1221211122021} is an apocalyptic number.

1221211122021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1221211122021 is a deficient number, since it is larger than the sum of its proper divisors (719025149979).

1221211122021 is a wasteful number, since it uses less digits than its factorization.

1221211122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101946038 (or 101946013 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 1221211122021 its reverse (1202211121221), we get a palindrome (2423422243242).

The spelling of 1221211122021 in words is "one trillion, two hundred twenty-one billion, two hundred eleven million, one hundred twenty-two thousand, twenty-one".