21112100 has 36 divisors (see below), whose sum is σ = 46577748. Its totient is φ = 8304000.

The previous prime is 21112093. The next prime is 21112103. The reversal of 21112100 is 121112.

It can be written as a sum of positive squares in 6 ways, for example, as 6853924 + 14258176 = 2618^2 + 3776^2 .

It is not an unprimeable number, because it can be changed into a prime (21112103) 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, 4370 + ... + 7830.

Almost surely, 2^21112100 is an apocalyptic number.

21112100 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 21112100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23288874).

21112100 is an abundant number, since it is smaller than the sum of its proper divisors (25465648).

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

21112100 is a wasteful number, since it uses less digits than its factorization.

21112100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3536 (or 3529 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 21112100 is about 4594.7905284137. The cubic root of 21112100 is about 276.3824600390.

Adding to 21112100 its reverse (121112), we get a palindrome (21233212).

It can be divided in two parts, 21112 and 100, that added together give a palindrome (21212).

The spelling of 21112100 in words is "twenty-one million, one hundred twelve thousand, one hundred".