1221121202111 has 4 divisors (see below), whose sum is σ = 1263228829800. Its totient is φ = 1179013574424.

The previous prime is 1221121202101. The next prime is 1221121202123. The reversal of 1221121202111 is 1112021211221.

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

It is a cyclic number.

It is not a de Polignac number, because 1221121202111 - 2¹⁰ = 1221121201087 is a prime.

It is a super-2 number, since 2×1221121202111² (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 1221121202111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221121202101) 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, 21053813801 + ... + 21053813858.

It is an arithmetic number, because the mean of its divisors is an integer number (315807207450).

Almost surely, 2^{1221121202111} is an apocalyptic number.

1221121202111 is a deficient number, since it is larger than the sum of its proper divisors (42107627689).

1221121202111 is an equidigital number, since it uses as much as digits as its factorization.

1221121202111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42107627688.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 1221121202111 its reverse (1112021211221), we get a palindrome (2333142413332).

The spelling of 1221121202111 in words is "one trillion, two hundred twenty-one billion, one hundred twenty-one million, two hundred two thousand, one hundred eleven".