21102020200 has 96 divisors (see below), whose sum is σ = 49688616600. Its totient is φ = 8333475840.

The previous prime is 21102020183. The next prime is 21102020231. The reversal of 21102020200 is 202020112.

It can be written as a sum of positive squares in 12 ways, for example, as 250082596 + 20851937604 = 15814^2 + 144402^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

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 23 ways as a sum of consecutive naturals, for example, 9873532 + ... + 9875668.

Almost surely, 2^21102020200 is an apocalyptic number.

21102020200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21102020200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24844308300).

21102020200 is an abundant number, since it is smaller than the sum of its proper divisors (28586596400).

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

21102020200 is a wasteful number, since it uses less digits than its factorization.

21102020200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2759 (or 2750 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 10.

Adding to 21102020200 its reverse (202020112), we get a palindrome (21304040312).

The spelling of 21102020200 in words is "twenty-one billion, one hundred two million, twenty thousand, two hundred".