21323020212 has 72 divisors (see below), whose sum is σ = 58620842280. Its totient is φ = 6495955200.

The previous prime is 21323020189. The next prime is 21323020217. The reversal of 21323020212 is 21202032312.

It can be written as a sum of positive squares in 4 ways, for example, as 11251693476 + 10071326736 = 106074^2 + 100356^2 .

It is a super-2 number, since 2×21323020212² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21323020217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 178287 + ... + 272822.

It is an arithmetic number, because the mean of its divisors is an integer number (814178365).

Almost surely, 2^21323020212 is an apocalyptic number.

It is an amenable number.

21323020212 is an abundant number, since it is smaller than the sum of its proper divisors (37297822068).

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

21323020212 is a wasteful number, since it uses less digits than its factorization.

21323020212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 451233 (or 451228 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

Adding to 21323020212 its reverse (21202032312), we get a palindrome (42525052524).

The spelling of 21323020212 in words is "twenty-one billion, three hundred twenty-three million, twenty thousand, two hundred twelve".