1211221111011 has 64 divisors (see below), whose sum is σ = 1683619531776. Its totient is φ = 773929728000.

The previous prime is 1211221110919. The next prime is 1211221111049. The reversal of 1211221111011 is 1101111221121.

It is not a de Polignac number, because 1211221111011 - 2¹⁷ = 1211220979939 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211221112011) 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, 1292658135 + ... + 1292659071.

It is an arithmetic number, because the mean of its divisors is an integer number (26306555184).

Almost surely, 2^{1211221111011} is an apocalyptic number.

1211221111011 is a deficient number, since it is larger than the sum of its proper divisors (472398420765).

1211221111011 is a wasteful number, since it uses less digits than its factorization.

1211221111011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1692.

The product of its (nonzero) digits is 8, while the sum is 15.

Adding to 1211221111011 its reverse (1101111221121), we get a palindrome (2312332332132).

It can be divided in two parts, 121122111 and 1011, that multiplied together give a palindrome (122454454221).

The spelling of 1211221111011 in words is "one trillion, two hundred eleven billion, two hundred twenty-one million, one hundred eleven thousand, eleven".