21212121284 has 24 divisors (see below), whose sum is σ = 39080496000. Its totient is φ = 10046423520.

The previous prime is 21212121283. The next prime is 21212121299. The reversal of 21212121284 is 48212121212.

It is not an unprimeable number, because it can be changed into a prime (21212121283) 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, 683954 + ... + 714294.

It is an arithmetic number, because the mean of its divisors is an integer number (1628354000).

Almost surely, 2^21212121284 is an apocalyptic number.

It is an amenable number.

21212121284 is a deficient number, since it is larger than the sum of its proper divisors (17868374716).

21212121284 is a wasteful number, since it uses less digits than its factorization.

21212121284 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39563 (or 39561 counting only the distinct ones).

The product of its digits is 1024, while the sum is 26.

Adding to 21212121284 its reverse (48212121212), we get a palindrome (69424242496).

The spelling of 21212121284 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-one thousand, two hundred eighty-four".