21212122200 has 96 divisors (see below), whose sum is σ = 67534881360. Its totient is φ = 5503680000.

The previous prime is 21212122199. The next prime is 21212122201. The reversal of 21212122200 is 222121212.

It is an interprime number because it is at equal distance from previous prime (21212122199) and next prime (21212122201).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21212122200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212122201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 455551 + ... + 499950.

Almost surely, 2^21212122200 is an apocalyptic number.

21212122200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212122200 is an abundant number, since it is smaller than the sum of its proper divisors (46322759160).

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

21212122200 is a wasteful number, since it uses less digits than its factorization.

21212122200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 955557 (or 955548 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

Adding to 21212122200 its reverse (222121212), we get a palindrome (21434243412).

The spelling of 21212122200 in words is "twenty-one billion, two hundred twelve million, one hundred twenty-two thousand, two hundred".