21111212200 has 48 divisors (see below), whose sum is σ = 52859233980. Its totient is φ = 7794908160.

The previous prime is 21111212197. The next prime is 21111212201. The reversal of 21111212200 is 221211112.

It can be written as a sum of positive squares in 6 ways, for example, as 3836315844 + 17274896356 = 61938^2 + 131434^2 .

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (21111212201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4057249 + ... + 4062448.

Almost surely, 2^21111212200 is an apocalyptic number.

21111212200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21111212200 is an abundant number, since it is smaller than the sum of its proper divisors (31748021780).

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

21111212200 is a wasteful number, since it uses less digits than its factorization.

21111212200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8119726 (or 8119717 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21111212200 its reverse (221211112), we get a palindrome (21332423312).

The spelling of 21111212200 in words is "twenty-one billion, one hundred eleven million, two hundred twelve thousand, two hundred".