1211111311 has 8 divisors (see below), whose sum is σ = 1257405120. Its totient is φ = 1165119648.

The previous prime is 1211111303. The next prime is 1211111333. The reversal of 1211111311 is 1131111121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1211111311 - 2³ = 1211111303 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1211111291 and 1211111300.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211111351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67351 + ... + 83416.

It is an arithmetic number, because the mean of its divisors is an integer number (157175640).

Almost surely, 2^1211111311 is an apocalyptic number.

1211111311 is a deficient number, since it is larger than the sum of its proper divisors (46293809).

1211111311 is a wasteful number, since it uses less digits than its factorization.

1211111311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 151073.

The product of its digits is 6, while the sum is 13.

The square root of 1211111311 is about 34801.0245682509. The cubic root of 1211111311 is about 1065.9283671052.

Adding to 1211111311 its reverse (1131111121), we get a palindrome (2342222432).

The spelling of 1211111311 in words is "one billion, two hundred eleven million, one hundred eleven thousand, three hundred eleven".