21045345 has 16 divisors (see below), whose sum is σ = 35137152. Its totient is φ = 10736000.

The previous prime is 21045319. The next prime is 21045377. The reversal of 21045345 is 54354012.

It is not a de Polignac number, because 21045345 - 2⁹ = 21044833 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30156 + ... + 30845.

It is an arithmetic number, because the mean of its divisors is an integer number (2196072).

Almost surely, 2^21045345 is an apocalyptic number.

It is an amenable number.

21045345 is a deficient number, since it is larger than the sum of its proper divisors (14091807).

21045345 is a wasteful number, since it uses less digits than its factorization.

21045345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61032.

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

The square root of 21045345 is about 4587.5205721610. The cubic root of 21045345 is about 276.0908517333.

Adding to 21045345 its reverse (54354012), we get a palindrome (75399357).

The spelling of 21045345 in words is "twenty-one million, forty-five thousand, three hundred forty-five".