21100230 has 64 divisors (see below), whose sum is σ = 59590080. Its totient is φ = 5294592.

The previous prime is 21100217. The next prime is 21100231. The reversal of 21100230 is 3200112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2292 + ... + 6888.

It is an arithmetic number, because the mean of its divisors is an integer number (931095).

Almost surely, 2^21100230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21100230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29795040).

21100230 is an abundant number, since it is smaller than the sum of its proper divisors (38489850).

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

21100230 is a wasteful number, since it uses less digits than its factorization.

21100230 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4630 (or 4624 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 21100230 is about 4593.4986665939. The cubic root of 21100230 is about 276.3306528632.

Adding to 21100230 its reverse (3200112), we get a palindrome (24300342).

The spelling of 21100230 in words is "twenty-one million, one hundred thousand, two hundred thirty".