21224450 has 24 divisors (see below), whose sum is σ = 42515508. Its totient is φ = 7836480.

The previous prime is 21224447. The next prime is 21224479. The reversal of 21224450 is 5442212.

It is a happy number.

It is a Cunningham number, because it is equal to 4607²+1.

It can be written as a sum of positive squares in 6 ways, for example, as 3136441 + 18088009 = 1771^2 + 4253^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 15677 + ... + 16976.

Almost surely, 2^21224450 is an apocalyptic number.

21224450 is an abundant number, since it is smaller than the sum of its proper divisors (21291058).

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

21224450 is a wasteful number, since it uses less digits than its factorization.

21224450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32678 (or 32673 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 20.

The square root of 21224450 is about 4607.0001085305. Note that the first 3 decimals coincide. The cubic root of 21224450 is about 276.8718579101.

Adding to 21224450 its reverse (5442212), we get a palindrome (26666662).

The spelling of 21224450 in words is "twenty-one million, two hundred twenty-four thousand, four hundred fifty".