21304885 has 16 divisors (see below), whose sum is σ = 29454336. Its totient is φ = 14491008.

The previous prime is 21304873. The next prime is 21304889. The reversal of 21304885 is 58840312.

It is not a de Polignac number, because 21304885 - 2⁹ = 21304373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304889) 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, 2049 + ... + 6841.

It is an arithmetic number, because the mean of its divisors is an integer number (1840896).

Almost surely, 2^21304885 is an apocalyptic number.

It is an amenable number.

21304885 is a deficient number, since it is larger than the sum of its proper divisors (8149451).

21304885 is a wasteful number, since it uses less digits than its factorization.

21304885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4932.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 21304885 is about 4615.7215037305. The cubic root of 21304885 is about 277.2211738215.

The spelling of 21304885 in words is "twenty-one million, three hundred four thousand, eight hundred eighty-five".