21093205 has 32 divisors (see below), whose sum is σ = 30046464. Its totient is φ = 13917696.

The previous prime is 21093199. The next prime is 21093217. The reversal of 21093205 is 50239012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21093205 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 (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 153897 + ... + 154033.

It is an arithmetic number, because the mean of its divisors is an integer number (938952).

Almost surely, 2^21093205 is an apocalyptic number.

21093205 is the 2905-th heptagonal number.

It is an amenable number.

21093205 is a deficient number, since it is larger than the sum of its proper divisors (8953259).

21093205 is a wasteful number, since it uses less digits than its factorization.

21093205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285.

The product of its (nonzero) digits is 540, while the sum is 22.

The square root of 21093205 is about 4592.7339352503. The cubic root of 21093205 is about 276.2999827661.

The spelling of 21093205 in words is "twenty-one million, ninety-three thousand, two hundred five".