21030535 has 4 divisors (see below), whose sum is σ = 25236648. Its totient is φ = 16824424.

The previous prime is 21030469. The next prime is 21030551. The reversal of 21030535 is 53503012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21030535 - 2¹⁹ = 20506247 is a prime.

It is a Duffinian number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 2103049 + ... + 2103058.

It is an arithmetic number, because the mean of its divisors is an integer number (6309162).

Almost surely, 2^21030535 is an apocalyptic number.

21030535 is a deficient number, since it is larger than the sum of its proper divisors (4206113).

21030535 is an equidigital number, since it uses as much as digits as its factorization.

21030535 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4206112.

The product of its (nonzero) digits is 450, while the sum is 19.

The square root of 21030535 is about 4585.9061263833. The cubic root of 21030535 is about 276.0260731162.

Adding to 21030535 its reverse (53503012), we get a palindrome (74533547).

The spelling of 21030535 in words is "twenty-one million, thirty thousand, five hundred thirty-five".