21224145 has 8 divisors (see below), whose sum is σ = 33958656. Its totient is φ = 11319536.

The previous prime is 21224141. The next prime is 21224149. The reversal of 21224145 is 54142212.

It is an interprime number because it is at equal distance from previous prime (21224141) and next prime (21224149).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21224145 - 2² = 21224141 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21224141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 707457 + ... + 707486.

It is an arithmetic number, because the mean of its divisors is an integer number (4244832).

Almost surely, 2^21224145 is an apocalyptic number.

It is an amenable number.

21224145 is a deficient number, since it is larger than the sum of its proper divisors (12734511).

21224145 is a wasteful number, since it uses less digits than its factorization.

21224145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1414951.

The product of its digits is 640, while the sum is 21.

The square root of 21224145 is about 4606.9670066107. The cubic root of 21224145 is about 276.8705316673.

Adding to 21224145 its reverse (54142212), we get a palindrome (75366357).

The spelling of 21224145 in words is "twenty-one million, two hundred twenty-four thousand, one hundred forty-five".