21102021200 has 60 divisors (see below), whose sum is σ = 54597435228. Its totient is φ = 7791513600.

The previous prime is 21102021151. The next prime is 21102021211. The reversal of 21102021200 is 212020112.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 87459904 + 21014561296 = 9352^2 + 144964^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2023841 + ... + 2034240.

Almost surely, 2^21102021200 is an apocalyptic number.

21102021200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21102021200 is an abundant number, since it is smaller than the sum of its proper divisors (33495414028).

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

21102021200 is a wasteful number, since it uses less digits than its factorization.

21102021200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4058112 (or 4058101 counting only the distinct ones).

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

Adding to 21102021200 its reverse (212020112), we get a palindrome (21314041312).

The spelling of 21102021200 in words is "twenty-one billion, one hundred two million, twenty-one thousand, two hundred".