21075365 has 4 divisors (see below), whose sum is σ = 25290444. Its totient is φ = 16860288.

The previous prime is 21075349. The next prime is 21075371. The reversal of 21075365 is 56357012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12159169 + 8916196 = 3487^2 + 2986^2 .

It is a cyclic number.

It is not a de Polignac number, because 21075365 - 2⁴ = 21075349 is a prime.

It is a Duffinian number.

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 3 ways as a sum of consecutive naturals, for example, 2107532 + ... + 2107541.

It is an arithmetic number, because the mean of its divisors is an integer number (6322611).

Almost surely, 2^21075365 is an apocalyptic number.

It is an amenable number.

21075365 is a deficient number, since it is larger than the sum of its proper divisors (4215079).

21075365 is an equidigital number, since it uses as much as digits as its factorization.

21075365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4215078.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21075365 is about 4590.7913261223. The cubic root of 21075365 is about 276.2220653830. Note that the first 3 decimals are identical.

The spelling of 21075365 in words is "twenty-one million, seventy-five thousand, three hundred sixty-five".