21030525 has 36 divisors (see below), whose sum is σ = 37978720. Its totient is φ = 11124000.

The previous prime is 21030469. The next prime is 21030551. The reversal of 21030525 is 52503012.

It is a happy number.

It is not a de Polignac number, because 21030525 - 2¹¹ = 21028477 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 21030498 and 21030507.

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 35 ways as a sum of consecutive naturals, for example, 33666 + ... + 34284.

Almost surely, 2^21030525 is an apocalyptic number.

21030525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21030525 is a deficient number, since it is larger than the sum of its proper divisors (16948195).

21030525 is a wasteful number, since it uses less digits than its factorization.

21030525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 786 (or 778 counting only the distinct ones).

The product of its (nonzero) digits is 300, while the sum is 18.

The square root of 21030525 is about 4585.9050360861. The cubic root of 21030525 is about 276.0260293662.

Adding to 21030525 its reverse (52503012), we get a palindrome (73533537).

The spelling of 21030525 in words is "twenty-one million, thirty thousand, five hundred twenty-five".