21535105 has 4 divisors (see below), whose sum is σ = 25842132. Its totient is φ = 17228080.

The previous prime is 21535093. The next prime is 21535121. The reversal of 21535105 is 50153512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11498881 + 10036224 = 3391^2 + 3168^2 .

It is not a de Polignac number, because 21535105 - 2¹⁵ = 21502337 is a prime.

It is a super-2 number, since 2×21535105² = 927521494722050, which contains 22 as substring.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2153506 + ... + 2153515.

It is an arithmetic number, because the mean of its divisors is an integer number (6460533).

Almost surely, 2^21535105 is an apocalyptic number.

It is an amenable number.

21535105 is a deficient number, since it is larger than the sum of its proper divisors (4307027).

21535105 is an equidigital number, since it uses as much as digits as its factorization.

21535105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4307026.

The product of its (nonzero) digits is 750, while the sum is 22.

The square root of 21535105 is about 4640.5931732915. The cubic root of 21535105 is about 278.2161466192.

Adding to 21535105 its reverse (50153512), we get a palindrome (71688617).

The spelling of 21535105 in words is "twenty-one million, five hundred thirty-five thousand, one hundred five".