21112122011 has 4 divisors (see below), whose sum is σ = 21321153024. Its totient is φ = 20903091000.

The previous prime is 21112121999. The next prime is 21112122079. The reversal of 21112122011 is 11022121112.

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 21112122011 - 2²⁶ = 21045013147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21112122091) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104515355 + ... + 104515556.

It is an arithmetic number, because the mean of its divisors is an integer number (5330288256).

Almost surely, 2^21112122011 is an apocalyptic number.

21112122011 is a deficient number, since it is larger than the sum of its proper divisors (209031013).

21112122011 is a wasteful number, since it uses less digits than its factorization.

21112122011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209031012.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21112122011 its reverse (11022121112), we get a palindrome (32134243123).

The spelling of 21112122011 in words is "twenty-one billion, one hundred twelve million, one hundred twenty-two thousand, eleven".