21943305 has 20 divisors (see below), whose sum is σ = 39336132. Its totient is φ = 11702880.

The previous prime is 21943303. The next prime is 21943321. The reversal of 21943305 is 50334912.

It can be written as a sum of positive squares in 2 ways, for example, as 2653641 + 19289664 = 1629^2 + 4392^2 .

It is not a de Polignac number, because 21943305 - 2¹ = 21943303 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21943301) 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 19 ways as a sum of consecutive naturals, for example, 26686 + ... + 27495.

Almost surely, 2^21943305 is an apocalyptic number.

It is an amenable number.

21943305 is a deficient number, since it is larger than the sum of its proper divisors (17392827).

21943305 is an equidigital number, since it uses as much as digits as its factorization.

21943305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54198 (or 54189 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21943305 is about 4684.3681537642. The cubic root of 21943305 is about 279.9630265805.

The spelling of 21943305 in words is "twenty-one million, nine hundred forty-three thousand, three hundred five".