21002221212 has 24 divisors (see below), whose sum is σ = 56005923456. Its totient is φ = 6000634608.

The previous prime is 21002221199. The next prime is 21002221223. The reversal of 21002221212 is 21212220012.

It is a junction number, because it is equal to n+sod(n) for n = 21002221191 and 21002221200.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125013138 + ... + 125013305.

It is an arithmetic number, because the mean of its divisors is an integer number (2333580144).

Almost surely, 2^21002221212 is an apocalyptic number.

It is an amenable number.

21002221212 is an abundant number, since it is smaller than the sum of its proper divisors (35003702244).

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

21002221212 is a wasteful number, since it uses less digits than its factorization.

21002221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250026457 (or 250026455 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21002221212 its reverse (21212220012), we get a palindrome (42214441224).

The spelling of 21002221212 in words is "twenty-one billion, two million, two hundred twenty-one thousand, two hundred twelve".