1211001111111 has 32 divisors (see below), whose sum is σ = 1786665553920. Its totient is φ = 723499632000.

The previous prime is 1211001111097. The next prime is 1211001111137. The reversal of 1211001111111 is 1111111001121.

It is not a de Polignac number, because 1211001111111 - 2⁵ = 1211001111079 is a prime.

It is a super-2 number, since 2×1211001111111² (a number of 25 digits) contains 22 as substring.

1211001111111 is a modest number, since divided by 1111111 gives 121100 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211001111161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30055 + ... + 1556568.

It is an arithmetic number, because the mean of its divisors is an integer number (55833298560).

Almost surely, 2^{1211001111111} is an apocalyptic number.

1211001111111 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1211001111111 is a deficient number, since it is larger than the sum of its proper divisors (575664442809).

1211001111111 is a wasteful number, since it uses less digits than its factorization.

1211001111111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1586967.

The product of its (nonzero) digits is 2, while the sum is 12.

Adding to 1211001111111 its reverse (1111111001121), we get a palindrome (2322112112232).

The spelling of 1211001111111 in words is "one trillion, two hundred eleven billion, one million, one hundred eleven thousand, one hundred eleven".