21803100 has 72 divisors (see below), whose sum is σ = 68828928. Its totient is φ = 5284800.

The previous prime is 21803083. The next prime is 21803141. The reversal of 21803100 is 130812.

It is a happy number.

It is a super-2 number, since 2×21803100² = 950750339220000, which contains 22 as substring.

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 21803100.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4 + ... + 6603.

Almost surely, 2^21803100 is an apocalyptic number.

21803100 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 21803100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34414464).

21803100 is an abundant number, since it is smaller than the sum of its proper divisors (47025828).

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

21803100 is a wasteful number, since it uses less digits than its factorization.

21803100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6635 (or 6628 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 21803100 is about 4669.3789736966. The cubic root of 21803100 is about 279.3654849644.

Adding to 21803100 its reverse (130812), we get a palindrome (21933912).

The spelling of 21803100 in words is "twenty-one million, eight hundred three thousand, one hundred".