21224575 has 6 divisors (see below), whose sum is σ = 26318504. Its totient is φ = 16979640.

The previous prime is 21224563. The next prime is 21224579. The reversal of 21224575 is 57542212.

It is not a de Polignac number, because 21224575 - 2⁷ = 21224447 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224579) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 424467 + ... + 424516.

Almost surely, 2^21224575 is an apocalyptic number.

21224575 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21224575 is a deficient number, since it is larger than the sum of its proper divisors (5093929).

21224575 is an equidigital number, since it uses as much as digits as its factorization.

21224575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 848993 (or 848988 counting only the distinct ones).

The product of its digits is 5600, while the sum is 28.

The square root of 21224575 is about 4607.0136748223. The cubic root of 21224575 is about 276.8724014486.

Adding to 21224575 its reverse (57542212), we get a palindrome (78766787).

The spelling of 21224575 in words is "twenty-one million, two hundred twenty-four thousand, five hundred seventy-five".