21212200 has 48 divisors (see below), whose sum is σ = 50086080. Its totient is φ = 8352960.

The previous prime is 21212197. The next prime is 21212239. The reversal of 21212200 is 221212.

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

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, 12609 + ... + 14191.

It is an arithmetic number, because the mean of its divisors is an integer number (1043460).

Almost surely, 2^21212200 is an apocalyptic number.

21212200 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 21212200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25043040).

21212200 is an abundant number, since it is smaller than the sum of its proper divisors (28873880).

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

21212200 is a wasteful number, since it uses less digits than its factorization.

21212200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1666 (or 1657 counting only the distinct ones).

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

The square root of 21212200 is about 4605.6704180825. The cubic root of 21212200 is about 276.8185807857.

Adding to 21212200 its reverse (221212), we get a palindrome (21433412).

It can be divided in two parts, 21212 and 200, that added together give a palindrome (21412).

The spelling of 21212200 in words is "twenty-one million, two hundred twelve thousand, two hundred".