1211111011 has 4 divisors (see below), whose sum is σ = 1321212024. Its totient is φ = 1101010000.

The previous prime is 1211110987. The next prime is 1211111029. The reversal of 1211111011 is 1101111121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1211111011 - 2¹³ = 1211102819 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1211111081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55050490 + ... + 55050511.

It is an arithmetic number, because the mean of its divisors is an integer number (330303006).

Almost surely, 2^1211111011 is an apocalyptic number.

1211111011 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1211111011 is a deficient number, since it is larger than the sum of its proper divisors (110101013).

1211111011 is a wasteful number, since it uses less digits than its factorization.

1211111011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110101012.

The product of its (nonzero) digits is 2, while the sum is 10.

The square root of 1211111011 is about 34801.0202580327. The cubic root of 1211111011 is about 1065.9282790928.

Adding to 1211111011 its reverse (1101111121), we get a palindrome (2312222132).

It can be divided in two parts, 12111110 and 11, that added together give a palindrome (12111121).

The spelling of 1211111011 in words is "one billion, two hundred eleven million, one hundred eleven thousand, eleven".