1221222122211 has 64 divisors (see below), whose sum is σ = 2058596965376. Its totient is φ = 626636736000.

The previous prime is 1221222122209. The next prime is 1221222122233. The reversal of 1221222122211 is 1122212221221.

It is not a de Polignac number, because 1221222122211 - 2¹ = 1221222122209 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is not an unprimeable number, because it can be changed into a prime (1221222122711) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 100003896 + ... + 100016106.

It is an arithmetic number, because the mean of its divisors is an integer number (32165577584).

Almost surely, 2^{1221222122211} is an apocalyptic number.

1221222122211 is a deficient number, since it is larger than the sum of its proper divisors (837374843165).

1221222122211 is a wasteful number, since it uses less digits than its factorization.

1221222122211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22172.

The product of its digits is 256, while the sum is 21.

Adding to 1221222122211 its reverse (1122212221221), we get a palindrome (2343434343432).

The spelling of 1221222122211 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-two million, one hundred twenty-two thousand, two hundred eleven".