21100012200 has 144 divisors (see below), whose sum is σ = 72776262780. Its totient is φ = 5474580480.

The previous prime is 21100012189. The next prime is 21100012249. The reversal of 21100012200 is 221000112.

It can be written as a sum of positive squares in 6 ways, for example, as 11512860804 + 9587151396 = 107298^2 + 97914^2 .

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 91809 + ... + 225008.

Almost surely, 2^21100012200 is an apocalyptic number.

21100012200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100012200 is an abundant number, since it is smaller than the sum of its proper divisors (51676250580).

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

21100012200 is a wasteful number, since it uses less digits than its factorization.

21100012200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 316876 (or 316864 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21100012200 its reverse (221000112), we get a palindrome (21321012312).

The spelling of 21100012200 in words is "twenty-one billion, one hundred million, twelve thousand, two hundred".