21205354 has 16 divisors (see below), whose sum is σ = 32442120. Its totient is φ = 10393600.

The previous prime is 21205313. The next prime is 21205361. The reversal of 21205354 is 45350212.

It can be written as a sum of positive squares in 4 ways, for example, as 11377129 + 9828225 = 3373^2 + 3135^2 .

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 22362 + ... + 23290.

Almost surely, 2^21205354 is an apocalyptic number.

21205354 is a deficient number, since it is larger than the sum of its proper divisors (11236766).

21205354 is a wasteful number, since it uses less digits than its factorization.

21205354 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1145.

The product of its (nonzero) digits is 1200, while the sum is 22.

The square root of 21205354 is about 4604.9271438319. The cubic root of 21205354 is about 276.7887975491.

Adding to 21205354 its reverse (45350212), we get a palindrome (66555566).

The spelling of 21205354 in words is "twenty-one million, two hundred five thousand, three hundred fifty-four".