1221101022221 has 4 divisors (see below), whose sum is σ = 1221123555072. Its totient is φ = 1221078489372.

The previous prime is 1221101022209. The next prime is 1221101022259. The reversal of 1221101022221 is 1222201011221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1221101022221 - 2⁶ = 1221101022157 is a prime.

It is a super-2 number, since 2×1221101022221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1221101022221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221101022121) 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, 11184941 + ... + 11293586.

It is an arithmetic number, because the mean of its divisors is an integer number (305280888768).

Almost surely, 2^{1221101022221} is an apocalyptic number.

It is an amenable number.

1221101022221 is a deficient number, since it is larger than the sum of its proper divisors (22532851).

1221101022221 is an equidigital number, since it uses as much as digits as its factorization.

1221101022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22532850.

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

Adding to 1221101022221 its reverse (1222201011221), we get a palindrome (2443302033442).

The spelling of 1221101022221 in words is "one trillion, two hundred twenty-one billion, one hundred one million, twenty-two thousand, two hundred twenty-one".