21000021212 has 12 divisors (see below), whose sum is σ = 36790032720. Its totient is φ = 10488583296.

The previous prime is 21000021197. The next prime is 21000021221. The reversal of 21000021212 is 21212000012.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21000021193 and 21000021202.

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, 2852693 + ... + 2860044.

It is an arithmetic number, because the mean of its divisors is an integer number (3065836060).

Almost surely, 2^21000021212 is an apocalyptic number.

It is an amenable number.

21000021212 is a deficient number, since it is larger than the sum of its proper divisors (15790011508).

21000021212 is a wasteful number, since it uses less digits than its factorization.

21000021212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5713660 (or 5713658 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21000021212 its reverse (21212000012), we get a palindrome (42212021224).

The spelling of 21000021212 in words is "twenty-one billion, twenty-one thousand, two hundred twelve".