21641135 has 4 divisors (see below), whose sum is σ = 25969368. Its totient is φ = 17312904.

The previous prime is 21641117. The next prime is 21641143. The reversal of 21641135 is 53114612.

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 21641135 - 2¹⁶ = 21575599 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21641135.

It is a congruent 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, 2164109 + ... + 2164118.

It is an arithmetic number, because the mean of its divisors is an integer number (6492342).

Almost surely, 2^21641135 is an apocalyptic number.

21641135 is a deficient number, since it is larger than the sum of its proper divisors (4328233).

21641135 is an equidigital number, since it uses as much as digits as its factorization.

21641135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4328232.

The product of its digits is 720, while the sum is 23.

The square root of 21641135 is about 4652.0033318991. The cubic root of 21641135 is about 278.6720065736.

Adding to 21641135 its reverse (53114612), we get a palindrome (74755747).

The spelling of 21641135 in words is "twenty-one million, six hundred forty-one thousand, one hundred thirty-five".