21270265 has 4 divisors (see below), whose sum is σ = 25524324. Its totient is φ = 17016208.

The previous prime is 21270233. The next prime is 21270269. The reversal of 21270265 is 56207212.

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 16621929 + 4648336 = 4077^2 + 2156^2 .

It is a cyclic number.

It is not a de Polignac number, because 21270265 - 2⁵ = 21270233 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21270269) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 2127022 + ... + 2127031.

It is an arithmetic number, because the mean of its divisors is an integer number (6381081).

Almost surely, 2^21270265 is an apocalyptic number.

It is an amenable number.

21270265 is a deficient number, since it is larger than the sum of its proper divisors (4254059).

21270265 is an equidigital number, since it uses as much as digits as its factorization.

21270265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4254058.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 21270265 is about 4611.9697527195. The cubic root of 21270265 is about 277.0709328437.

Adding to 21270265 its reverse (56207212), we get a palindrome (77477477).

The spelling of 21270265 in words is "twenty-one million, two hundred seventy thousand, two hundred sixty-five".