21021020212 has 12 divisors (see below), whose sum is σ = 36800186500. Its totient is φ = 10506681216.

The previous prime is 21021020161. The next prime is 21021020239. The reversal of 21021020212 is 21202012012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 790509456 + 20230510756 = 28116^2 + 142234^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21021020192 and 21021020201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 944853 + ... + 966844.

Almost surely, 2^21021020212 is an apocalyptic number.

It is an amenable number.

21021020212 is a deficient number, since it is larger than the sum of its proper divisors (15779166288).

21021020212 is a wasteful number, since it uses less digits than its factorization.

21021020212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1914450 (or 1914448 counting only the distinct ones).

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

Adding to 21021020212 its reverse (21202012012), we get a palindrome (42223032224).

The spelling of 21021020212 in words is "twenty-one billion, twenty-one million, twenty thousand, two hundred twelve".