21408300 has 108 divisors (see below), whose sum is σ = 69667416. Its totient is φ = 5702400.

The previous prime is 21408251. The next prime is 21408301. The reversal of 21408300 is 380412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (108).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21408301) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 23860 + ... + 24740.

Almost surely, 2^21408300 is an apocalyptic number.

21408300 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 21408300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34833708).

21408300 is an abundant number, since it is smaller than the sum of its proper divisors (48259116).

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

21408300 is a wasteful number, since it uses less digits than its factorization.

21408300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 910 (or 891 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 21408300 is about 4626.9104162497. The cubic root of 21408300 is about 277.6689985923.

Adding to 21408300 its reverse (380412), we get a palindrome (21788712).

It can be divided in two parts, 2140 and 8300, that added together give a triangular number (10440 = T₁₄₄).

The spelling of 21408300 in words is "twenty-one million, four hundred eight thousand, three hundred".