21110012121 has 32 divisors (see below), whose sum is σ = 31041325440. Its totient is φ = 12654272000.

The previous prime is 21110012117. The next prime is 21110012129. The reversal of 21110012121 is 12121001112.

It is a cyclic number.

It is not a de Polignac number, because 21110012121 - 2² = 21110012117 is a prime.

It is a super-2 number, since 2×21110012121² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21110012097 and 21110012106.

It is not an unprimeable number, because it can be changed into a prime (21110012129) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3973615 + ... + 3978923.

It is an arithmetic number, because the mean of its divisors is an integer number (970041420).

Almost surely, 2^21110012121 is an apocalyptic number.

It is an amenable number.

21110012121 is a deficient number, since it is larger than the sum of its proper divisors (9931313319).

21110012121 is a wasteful number, since it uses less digits than its factorization.

21110012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6617.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21110012121 its reverse (12121001112), we get a palindrome (33231013233).

The spelling of 21110012121 in words is "twenty-one billion, one hundred ten million, twelve thousand, one hundred twenty-one".