21211021200 has 60 divisors (see below), whose sum is σ = 67945975088. Its totient is φ = 5656272000.

The previous prime is 21211021171. The next prime is 21211021213. The reversal of 21211021200 is 212011212.

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8836726 + ... + 8839125.

Almost surely, 2^21211021200 is an apocalyptic number.

21211021200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211021200 is an abundant number, since it is smaller than the sum of its proper divisors (46734953888).

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

21211021200 is a wasteful number, since it uses less digits than its factorization.

21211021200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17675872 (or 17675861 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21211021200 its reverse (212011212), we get a palindrome (21423032412).

The spelling of 21211021200 in words is "twenty-one billion, two hundred eleven million, twenty-one thousand, two hundred".