21535201 has 4 divisors (see below), whose sum is σ = 21725892. Its totient is φ = 21344512.

The previous prime is 21535187. The next prime is 21535231. The reversal of 21535201 is 10253512.

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 1500625 + 20034576 = 1225^2 + 4476^2 .

It is a cyclic number.

It is not a de Polignac number, because 21535201 - 2⁵ = 21535169 is a prime.

It is a super-2 number, since 2×21535201² = 927529764220802, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21535231) by changing a digit.

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, 95176 + ... + 95401.

It is an arithmetic number, because the mean of its divisors is an integer number (5431473).

Almost surely, 2^21535201 is an apocalyptic number.

It is an amenable number.

21535201 is a deficient number, since it is larger than the sum of its proper divisors (190691).

21535201 is a wasteful number, since it uses less digits than its factorization.

21535201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190690.

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

The square root of 21535201 is about 4640.6035167853. The cubic root of 21535201 is about 278.2165600327.

Adding to 21535201 its reverse (10253512), we get a palindrome (31788713).

It can be divided in two parts, 21535 and 201, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21535201 in words is "twenty-one million, five hundred thirty-five thousand, two hundred one".