21012021200 has 30 divisors (see below), whose sum is σ = 50481381894. Its totient is φ = 8404808320.

The previous prime is 21012021167. The next prime is 21012021203. The reversal of 21012021200 is 212021012.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 3547870096 + 17464151104 = 59564^2 + 132152^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012021203) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 26264627 + ... + 26265426.

Almost surely, 2^21012021200 is an apocalyptic number.

21012021200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21012021200 is an abundant number, since it is smaller than the sum of its proper divisors (29469360694).

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

21012021200 is a wasteful number, since it uses less digits than its factorization.

21012021200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52530071 (or 52530060 counting only the distinct ones).

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

Adding to 21012021200 its reverse (212021012), we get a palindrome (21224042212).

The spelling of 21012021200 in words is "twenty-one billion, twelve million, twenty-one thousand, two hundred".