21111212101212 has 72 divisors (see below), whose sum is σ = 53706216210192. Its totient is φ = 6992006112000.

The previous prime is 21111212101193. The next prime is 21111212101249. The reversal of 21111212101212 is 21210121211112.

It is a happy number.

21111212101212 is a `hidden beast` number, since 211 + 1 + 121 + 210 + 121 + 2 = 666.

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

It is a congruent number.

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, 244863712 + ... + 244949912.

It is an arithmetic number, because the mean of its divisors is an integer number (745919669586).

Almost surely, 2^{21111212101212} is an apocalyptic number.

It is an amenable number.

21111212101212 is an abundant number, since it is smaller than the sum of its proper divisors (32595004108980).

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

21111212101212 is a wasteful number, since it uses less digits than its factorization.

21111212101212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129699 (or 129694 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21111212101212 its reverse (21210121211112), we get a palindrome (42321333312324).

The spelling of 21111212101212 in words is "twenty-one trillion, one hundred eleven billion, two hundred twelve million, one hundred one thousand, two hundred twelve".