21300805 has 12 divisors (see below), whose sum is σ = 26979372. Its totient is φ = 16142400.

The previous prime is 21300791. The next prime is 21300833. The reversal of 21300805 is 50800312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 9474084 + 11826721 = 3078^2 + 3439^2 .

It is not a de Polignac number, because 21300805 - 2¹¹ = 21298757 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4096 + ... + 7705.

It is an arithmetic number, because the mean of its divisors is an integer number (2248281).

Almost surely, 2^21300805 is an apocalyptic number.

It is an amenable number.

21300805 is a deficient number, since it is larger than the sum of its proper divisors (5678567).

21300805 is a wasteful number, since it uses less digits than its factorization.

21300805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11844 (or 11825 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 19.

The square root of 21300805 is about 4615.2795148290. The cubic root of 21300805 is about 277.2034762434.

The spelling of 21300805 in words is "twenty-one million, three hundred thousand, eight hundred five".