21030345 has 24 divisors (see below), whose sum is σ = 41660736. Its totient is φ = 9613728.

The previous prime is 21030337. The next prime is 21030379. The reversal of 21030345 is 54303012.

It is not a de Polignac number, because 21030345 - 2³ = 21030337 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33067 + ... + 33696.

It is an arithmetic number, because the mean of its divisors is an integer number (1735864).

Almost surely, 2^21030345 is an apocalyptic number.

It is an amenable number.

21030345 is a deficient number, since it is larger than the sum of its proper divisors (20630391).

21030345 is a wasteful number, since it uses less digits than its factorization.

21030345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66781 (or 66778 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21030345 is about 4585.8854106922. The cubic root of 21030345 is about 276.0252418628.

Adding to 21030345 its reverse (54303012), we get a palindrome (75333357).

The spelling of 21030345 in words is "twenty-one million, thirty thousand, three hundred forty-five".