21012112111 has 8 divisors (see below), whose sum is σ = 21310608384. Its totient is φ = 20713686840.

The previous prime is 21012112109. The next prime is 21012112123. The reversal of 21012112111 is 11121121012.

It is a happy number.

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 21012112111 - 2¹ = 21012112109 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21012112091 and 21012112100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012112171) 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, 946606 + ... + 968548.

It is an arithmetic number, because the mean of its divisors is an integer number (2663826048).

Almost surely, 2^21012112111 is an apocalyptic number.

21012112111 is a deficient number, since it is larger than the sum of its proper divisors (298496273).

21012112111 is a wasteful number, since it uses less digits than its factorization.

21012112111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35501.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21012112111 its reverse (11121121012), we get a palindrome (32133233123).

The spelling of 21012112111 in words is "twenty-one billion, twelve million, one hundred twelve thousand, one hundred eleven".