21228300 has 108 divisors (see below), whose sum is σ = 67478320. Its totient is φ = 5581440.

The previous prime is 21228289. The next prime is 21228307. The reversal of 21228300 is 382212.

It is a happy number.

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 (21228307) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 92586 + ... + 92814.

Almost surely, 2^21228300 is an apocalyptic number.

21228300 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 21228300, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33739160).

21228300 is an abundant number, since it is smaller than the sum of its proper divisors (46250020).

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

21228300 is a wasteful number, since it uses less digits than its factorization.

21228300 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 352 (or 342 counting only the distinct ones).

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

The square root of 21228300 is about 4607.4179319875. The cubic root of 21228300 is about 276.8885979153. Note that the first 3 decimals are identical.

It can be divided in two parts, 21228 and 300, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 21228300 in words is "twenty-one million, two hundred twenty-eight thousand, three hundred".