21000221212 has 12 divisors (see below), whose sum is σ = 36751916880. Its totient is φ = 10499673536.

The previous prime is 21000221189. The next prime is 21000221243. The reversal of 21000221212 is 21212200012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21000221192 and 21000221201.

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 3 ways as a sum of consecutive naturals, for example, 14388 + ... + 205444.

It is an arithmetic number, because the mean of its divisors is an integer number (3062659740).

Almost surely, 2^21000221212 is an apocalyptic number.

It is an amenable number.

21000221212 is a deficient number, since it is larger than the sum of its proper divisors (15751695668).

21000221212 is a wasteful number, since it uses less digits than its factorization.

21000221212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218540 (or 218538 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21000221212 its reverse (21212200012), we get a palindrome (42212421224).

The spelling of 21000221212 in words is "twenty-one billion, two hundred twenty-one thousand, two hundred twelve".