21304855 has 32 divisors (see below), whose sum is σ = 30481920. Its totient is φ = 14090880.

The previous prime is 21304847. The next prime is 21304867. The reversal of 21304855 is 55840312.

It is not a de Polignac number, because 21304855 - 2³ = 21304847 is a prime.

It is a congruent 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 31 ways as a sum of consecutive naturals, for example, 59166 + ... + 59524.

It is an arithmetic number, because the mean of its divisors is an integer number (952560).

Almost surely, 2^21304855 is an apocalyptic number.

21304855 is a deficient number, since it is larger than the sum of its proper divisors (9177065).

21304855 is a wasteful number, since it uses less digits than its factorization.

21304855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 471.

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 21304855 is about 4615.7182539665. The cubic root of 21304855 is about 277.2210437005.

The spelling of 21304855 in words is "twenty-one million, three hundred four thousand, eight hundred fifty-five".