21110121011 has 16 divisors (see below), whose sum is σ = 24494413824. Its totient is φ = 17818156224.

The previous prime is 21110121001. The next prime is 21110121013. The reversal of 21110121011 is 11012101112.

It is a cyclic number.

It is not a de Polignac number, because 21110121011 - 2²⁶ = 21043012147 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21110120983 and 21110121001.

It is not an unprimeable number, because it can be changed into a prime (21110121013) 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, 1791806 + ... + 1803548.

It is an arithmetic number, because the mean of its divisors is an integer number (1530900864).

Almost surely, 2^21110121011 is an apocalyptic number.

21110121011 is a deficient number, since it is larger than the sum of its proper divisors (3384292813).

21110121011 is a wasteful number, since it uses less digits than its factorization.

21110121011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15650.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21110121011 its reverse (11012101112), we get a palindrome (32122222123).

The spelling of 21110121011 in words is "twenty-one billion, one hundred ten million, one hundred twenty-one thousand, eleven".