21035521 has 8 divisors (see below), whose sum is σ = 22992704. Its totient is φ = 19126800.

The previous prime is 21035519. The next prime is 21035533. The reversal of 21035521 is 12553012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21035521 - 2¹ = 21035519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21035551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11205 + ... + 12946.

It is an arithmetic number, because the mean of its divisors is an integer number (2874088).

Almost surely, 2^21035521 is an apocalyptic number.

It is an amenable number.

21035521 is a deficient number, since it is larger than the sum of its proper divisors (1957183).

21035521 is a wasteful number, since it uses less digits than its factorization.

21035521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24231.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 21035521 is about 4586.4497162838. The cubic root of 21035521 is about 276.0478851663.

Adding to 21035521 its reverse (12553012), we get a palindrome (33588533).

The spelling of 21035521 in words is "twenty-one million, thirty-five thousand, five hundred twenty-one".