1221221101111 has 16 divisors (see below), whose sum is σ = 1363048759296. Its totient is φ = 1084769100000.

The previous prime is 1221221101109. The next prime is 1221221101127. The reversal of 1221221101111 is 1111011221221.

It is not a de Polignac number, because 1221221101111 - 2¹ = 1221221101109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221221101141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5925175 + ... + 6127816.

It is an arithmetic number, because the mean of its divisors is an integer number (85190547456).

Almost surely, 2^{1221221101111} is an apocalyptic number.

1221221101111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1221221101111 is a deficient number, since it is larger than the sum of its proper divisors (141827658185).

1221221101111 is a wasteful number, since it uses less digits than its factorization.

1221221101111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12053214.

The product of its (nonzero) digits is 16, while the sum is 16.

Adding to 1221221101111 its reverse (1111011221221), we get a palindrome (2332232322332).

The spelling of 1221221101111 in words is "one trillion, two hundred twenty-one billion, two hundred twenty-one million, one hundred one thousand, one hundred eleven".