21030015 has 16 divisors (see below), whose sum is σ = 33804288. Its totient is φ = 11163936.

The previous prime is 21030001. The next prime is 21030043. The reversal of 21030015 is 51003012.

It is not a de Polignac number, because 21030015 - 2⁶ = 21029951 is a prime.

It is a congruent number.

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, 202 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (2112768).

Almost surely, 2^21030015 is an apocalyptic number.

21030015 is a deficient number, since it is larger than the sum of its proper divisors (12774273).

21030015 is a wasteful number, since it uses less digits than its factorization.

21030015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6518.

The product of its (nonzero) digits is 30, while the sum is 12.

The square root of 21030015 is about 4585.8494305854. The cubic root of 21030015 is about 276.0237980950.

Adding to 21030015 its reverse (51003012), we get a palindrome (72033027).

The spelling of 21030015 in words is "twenty-one million, thirty thousand, fifteen".