21212312212 has 48 divisors (see below), whose sum is σ = 47674513152. Its totient is φ = 8026824960.

The previous prime is 21212312171. The next prime is 21212312273. The reversal of 21212312212 is 21221321212.

It is a self number, because there is not a number n which added to its sum of digits gives 21212312212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1258489 + ... + 1275232.

It is an arithmetic number, because the mean of its divisors is an integer number (993219024).

Almost surely, 2^21212312212 is an apocalyptic number.

It is an amenable number.

21212312212 is an abundant number, since it is smaller than the sum of its proper divisors (26462200940).

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

21212312212 is a wasteful number, since it uses less digits than its factorization.

21212312212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2533768 (or 2533766 counting only the distinct ones).

The product of its digits is 192, while the sum is 19.

Adding to 21212312212 its reverse (21221321212), we get a palindrome (42433633424).

The spelling of 21212312212 in words is "twenty-one billion, two hundred twelve million, three hundred twelve thousand, two hundred twelve".