21230550 has 72 divisors (see below), whose sum is σ = 62239320. Its totient is φ = 5145600.

The previous prime is 21230549. The next prime is 21230551. The reversal of 21230550 is 5503212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21230549) and next prime (21230551).

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

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230551) 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, 2806 + ... + 7094.

It is an arithmetic number, because the mean of its divisors is an integer number (864435).

Almost surely, 2^21230550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21230550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31119660).

21230550 is an abundant number, since it is smaller than the sum of its proper divisors (41008770).

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

21230550 is a wasteful number, since it uses less digits than its factorization.

21230550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4318 (or 4310 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21230550 is about 4607.6620969858. The cubic root of 21230550 is about 276.8983800981.

Adding to 21230550 its reverse (5503212), we get a palindrome (26733762).

The spelling of 21230550 in words is "twenty-one million, two hundred thirty thousand, five hundred fifty".