1221221011211 has 4 divisors (see below), whose sum is σ = 1221852788112. Its totient is φ = 1220589234312.

The previous prime is 1221221011201. The next prime is 1221221011229. The reversal of 1221221011211 is 1121101221221.

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-1221221011211 is a prime.

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 1221221011211.

It is not an unprimeable number, because it can be changed into a prime (1221221011201) 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, 315885551 + ... + 315889416.

It is an arithmetic number, because the mean of its divisors is an integer number (305463197028).

Almost surely, 2^{1221221011211} is an apocalyptic number.

1221221011211 is a deficient number, since it is larger than the sum of its proper divisors (631776901).

1221221011211 is an equidigital number, since it uses as much as digits as its factorization.

1221221011211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631776900.

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

Adding to 1221221011211 its reverse (1121101221221), we get a palindrome (2342322232432).

The spelling of 1221221011211 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, eleven thousand, two hundred eleven".