21101111001111 has 16 divisors (see below), whose sum is σ = 28321443338240. Its totient is φ = 13974095008800.

The previous prime is 21101111001109. The next prime is 21101111001133. The reversal of 21101111001111 is 11110011110112.

It is not a de Polignac number, because 21101111001111 - 2¹ = 21101111001109 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101111001011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 55401921 + ... + 55781493.

It is an arithmetic number, because the mean of its divisors is an integer number (1770090208640).

Almost surely, 2^{21101111001111} is an apocalyptic number.

21101111001111 is a deficient number, since it is larger than the sum of its proper divisors (7220332337129).

21101111001111 is a wasteful number, since it uses less digits than its factorization.

21101111001111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502446.

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

Adding to 21101111001111 its reverse (11110011110112), we get a palindrome (32211122111223).

The spelling of 21101111001111 in words is "twenty-one trillion, one hundred one billion, one hundred eleven million, one thousand, one hundred eleven".