21112012121 has 8 divisors (see below), whose sum is σ = 21137756544. Its totient is φ = 21086285920.

The previous prime is 21112012069. The next prime is 21112012147. The reversal of 21112012121 is 12121021112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21112012121 - 2¹⁰ = 21112011097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21112012096 and 21112012105.

It is not an unprimeable number, because it can be changed into a prime (21112012321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5396156 + ... + 5400066.

It is an arithmetic number, because the mean of its divisors is an integer number (2642219568).

Almost surely, 2^21112012121 is an apocalyptic number.

It is an amenable number.

21112012121 is a deficient number, since it is larger than the sum of its proper divisors (25744423).

21112012121 is a wasteful number, since it uses less digits than its factorization.

21112012121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9111.

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

Adding to 21112012121 its reverse (12121021112), we get a palindrome (33233033233).

The spelling of 21112012121 in words is "twenty-one billion, one hundred twelve million, twelve thousand, one hundred twenty-one".