21223545 has 16 divisors (see below), whose sum is σ = 38808960. Its totient is φ = 9702144.

The previous prime is 21223519. The next prime is 21223583. The reversal of 21223545 is 54532212.

It is not a de Polignac number, because 21223545 - 2¹² = 21219449 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 100960 + ... + 101169.

It is an arithmetic number, because the mean of its divisors is an integer number (2425560).

Almost surely, 2^21223545 is an apocalyptic number.

It is an amenable number.

21223545 is a deficient number, since it is larger than the sum of its proper divisors (17585415).

21223545 is a wasteful number, since it uses less digits than its factorization.

21223545 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202144.

The product of its digits is 2400, while the sum is 24.

The square root of 21223545 is about 4606.9018873859. The cubic root of 21223545 is about 276.8679226280.

Adding to 21223545 its reverse (54532212), we get a palindrome (75755757).

The spelling of 21223545 in words is "twenty-one million, two hundred twenty-three thousand, five hundred forty-five".