21111121111212 has 72 divisors (see below), whose sum is σ = 58232697279120. Its totient is φ = 6395421352320.

The previous prime is 21111121111187. The next prime is 21111121111243. The reversal of 21111121111212 is 21211112111112.

21111121111212 is a `hidden beast` number, since 211 + 11 + 121 + 111 + 212 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6523243 + ... + 9207330.

It is an arithmetic number, because the mean of its divisors is an integer number (808787462210).

Almost surely, 2^{21111121111212} is an apocalyptic number.

21111121111212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21111121111212 is an abundant number, since it is smaller than the sum of its proper divisors (37121576167908).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21111121111212 is a wasteful number, since it uses less digits than its factorization.

21111121111212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15733983 (or 15733978 counting only the distinct ones).

The product of its digits is 16, while the sum is 18.

Adding to 21111121111212 its reverse (21211112111112), we get a palindrome (42322233222324).

The spelling of 21111121111212 in words is "twenty-one trillion, one hundred eleven billion, one hundred twenty-one million, one hundred eleven thousand, two hundred twelve".