21205353 has 16 divisors (see below), whose sum is σ = 31026240. Its totient is φ = 12801984.

The previous prime is 21205313. The next prime is 21205361. The reversal of 21205353 is 35350212.

It is not a de Polignac number, because 21205353 - 2¹⁰ = 21204329 is a prime.

21205353 is a modest number, since divided by 5353 gives 2120 as remainder.

It is not an unprimeable number, because it can be changed into a prime (21205313) 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 15 ways as a sum of consecutive naturals, for example, 3063 + ... + 7196.

It is an arithmetic number, because the mean of its divisors is an integer number (1939140).

Almost surely, 2^21205353 is an apocalyptic number.

It is an amenable number.

21205353 is a deficient number, since it is larger than the sum of its proper divisors (9820887).

21205353 is a wasteful number, since it uses less digits than its factorization.

21205353 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10328.

The product of its (nonzero) digits is 900, while the sum is 21.

The square root of 21205353 is about 4604.9270352526. The cubic root of 21205353 is about 276.7887931982.

Adding to 21205353 its reverse (35350212), we get a palindrome (56555565).

The spelling of 21205353 in words is "twenty-one million, two hundred five thousand, three hundred fifty-three".