21101111212 has 24 divisors (see below), whose sum is σ = 39141779040. Its totient is φ = 9919100160.

The previous prime is 21101111189. The next prime is 21101111221. The reversal of 21101111212 is 21211110112.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21101111192 and 21101111201.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 106339 + ... + 231322.

It is an arithmetic number, because the mean of its divisors is an integer number (1630907460).

Almost surely, 2^21101111212 is an apocalyptic number.

It is an amenable number.

21101111212 is a deficient number, since it is larger than the sum of its proper divisors (18040667828).

21101111212 is a wasteful number, since it uses less digits than its factorization.

21101111212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338601 (or 338599 counting only the distinct ones).

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

Adding to 21101111212 its reverse (21211110112), we get a palindrome (42312221324).

The spelling of 21101111212 in words is "twenty-one billion, one hundred one million, one hundred eleven thousand, two hundred twelve".