21204355 has 8 divisors (see below), whose sum is σ = 26942112. Its totient is φ = 15965568.

The previous prime is 21204349. The next prime is 21204397. The reversal of 21204355 is 55340212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21204355 - 2³ = 21204347 is a prime.

It is a Duffinian number.

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, 124647 + ... + 124816.

It is an arithmetic number, because the mean of its divisors is an integer number (3367764).

Almost surely, 2^21204355 is an apocalyptic number.

21204355 is a deficient number, since it is larger than the sum of its proper divisors (5737757).

21204355 is a wasteful number, since it uses less digits than its factorization.

21204355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 249485.

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

The square root of 21204355 is about 4604.8186717829. The cubic root of 21204355 is about 276.7844509055.

Adding to 21204355 its reverse (55340212), we get a palindrome (76544567).

The spelling of 21204355 in words is "twenty-one million, two hundred four thousand, three hundred fifty-five".