21103300 has 72 divisors (see below), whose sum is σ = 49996800. Its totient is φ = 7701120.

The previous prime is 21103267. The next prime is 21103301. The reversal of 21103300 is 330112.

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

It is not an unprimeable number, because it can be changed into a prime (21103301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 54909 + ... + 55291.

It is an arithmetic number, because the mean of its divisors is an integer number (694400).

Almost surely, 2^21103300 is an apocalyptic number.

21103300 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 21103300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24998400).

21103300 is an abundant number, since it is smaller than the sum of its proper divisors (28893500).

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

21103300 is a wasteful number, since it uses less digits than its factorization.

21103300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 445 (or 438 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 21103300 is about 4593.8328223826. The cubic root of 21103300 is about 276.3440538856.

Adding to 21103300 its reverse (330112), we get a palindrome (21433412).

The spelling of 21103300 in words is "twenty-one million, one hundred three thousand, three hundred".