21225450 has 48 divisors (see below), whose sum is σ = 53407296. Its totient is φ = 5577600.

The previous prime is 21225437. The next prime is 21225473. The reversal of 21225450 is 5452212.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9654 + ... + 11646.

It is an arithmetic number, because the mean of its divisors is an integer number (1112652).

Almost surely, 2^21225450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21225450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26703648).

21225450 is an abundant number, since it is smaller than the sum of its proper divisors (32181846).

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

21225450 is a wasteful number, since it uses less digits than its factorization.

21225450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2079 (or 2074 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

The square root of 21225450 is about 4607.1086377467. The cubic root of 21225450 is about 276.8762061580.

Adding to 21225450 its reverse (5452212), we get a palindrome (26677662).

The spelling of 21225450 in words is "twenty-one million, two hundred twenty-five thousand, four hundred fifty".