21202021212 has 12 divisors (see below), whose sum is σ = 49471382856. Its totient is φ = 7067340400.

The previous prime is 21202021201. The next prime is 21202021219. The reversal of 21202021212 is 21212020212.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 21202021191 and 21202021200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202021219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883417539 + ... + 883417562.

It is an arithmetic number, because the mean of its divisors is an integer number (4122615238).

Almost surely, 2^21202021212 is an apocalyptic number.

It is an amenable number.

21202021212 is an abundant number, since it is smaller than the sum of its proper divisors (28269361644).

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

21202021212 is a wasteful number, since it uses less digits than its factorization.

21202021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1766835108 (or 1766835106 counting only the distinct ones).

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

Adding to 21202021212 its reverse (21212020212), we get a palindrome (42414041424).

The spelling of 21202021212 in words is "twenty-one billion, two hundred two million, twenty-one thousand, two hundred twelve".