21168213212 has 6 divisors (see below), whose sum is σ = 37044373128. Its totient is φ = 10584106604.

The previous prime is 21168213167. The next prime is 21168213239. The reversal of 21168213212 is 21231286112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2646026648 + ... + 2646026655.

It is an arithmetic number, because the mean of its divisors is an integer number (6174062188).

Almost surely, 2^21168213212 is an apocalyptic number.

It is an amenable number.

21168213212 is a deficient number, since it is larger than the sum of its proper divisors (15876159916).

21168213212 is a wasteful number, since it uses less digits than its factorization.

21168213212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5292053307 (or 5292053305 counting only the distinct ones).

The product of its digits is 2304, while the sum is 29.

Adding to 21168213212 its reverse (21231286112), we get a palindrome (42399499324).

The spelling of 21168213212 in words is "twenty-one billion, one hundred sixty-eight million, two hundred thirteen thousand, two hundred twelve".