21224445 has 32 divisors (see below), whose sum is σ = 37255680. Its totient is φ = 10232640.

The previous prime is 21224431. The next prime is 21224447. The reversal of 21224445 is 54442212.

It is a happy number.

It is not a de Polignac number, because 21224445 - 2¹² = 21220349 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 50446 + ... + 50864.

It is an arithmetic number, because the mean of its divisors is an integer number (1164240).

Almost surely, 2^21224445 is an apocalyptic number.

It is an amenable number.

21224445 is a deficient number, since it is larger than the sum of its proper divisors (16031235).

21224445 is a wasteful number, since it uses less digits than its factorization.

21224445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 745.

The product of its digits is 2560, while the sum is 24.

The square root of 21224445 is about 4606.9995658780. Note that the first 3 decimals coincide. The cubic root of 21224445 is about 276.8718361685.

Adding to 21224445 its reverse (54442212), we get a palindrome (75666657).

The spelling of 21224445 in words is "twenty-one million, two hundred twenty-four thousand, four hundred forty-five".