21030513 has 16 divisors (see below), whose sum is σ = 33932160. Its totient is φ = 11310336.

The previous prime is 21030469. The next prime is 21030551. The reversal of 21030513 is 31503012.

It is a happy number.

It is not a de Polignac number, because 21030513 - 2⁹ = 21030001 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21030492 and 21030501.

It is not an unprimeable number, because it can be changed into a prime (21030553) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 29098 + ... + 29811.

It is an arithmetic number, because the mean of its divisors is an integer number (2120760).

Almost surely, 2^21030513 is an apocalyptic number.

It is an amenable number.

21030513 is a deficient number, since it is larger than the sum of its proper divisors (12901647).

21030513 is a wasteful number, since it uses less digits than its factorization.

21030513 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58936.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21030513 is about 4585.9037277291. The cubic root of 21030513 is about 276.0259768661.

Adding to 21030513 its reverse (31503012), we get a palindrome (52533525).

The spelling of 21030513 in words is "twenty-one million, thirty thousand, five hundred thirteen".