21121111311 has 16 divisors (see below), whose sum is σ = 28703144448. Its totient is φ = 13811924000.

The previous prime is 21121111279. The next prime is 21121111381. The reversal of 21121111311 is 11311112112.

It is a cyclic number.

It is not a de Polignac number, because 21121111311 - 2⁵ = 21121111279 is a prime.

It is a super-2 number, since 2×21121111311² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121111381) 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 15 ways as a sum of consecutive naturals, for example, 209715 + ... + 293636.

It is an arithmetic number, because the mean of its divisors is an integer number (1793946528).

Almost surely, 2^21121111311 is an apocalyptic number.

21121111311 is a deficient number, since it is larger than the sum of its proper divisors (7582033137).

21121111311 is a wasteful number, since it uses less digits than its factorization.

21121111311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 503622.

The product of its digits is 12, while the sum is 15.

Adding to 21121111311 its reverse (11311112112), we get a palindrome (32432223423).

The spelling of 21121111311 in words is "twenty-one billion, one hundred twenty-one million, one hundred eleven thousand, three hundred eleven".