21063265 has 4 divisors (see below), whose sum is σ = 25275924. Its totient is φ = 16850608.

The previous prime is 21063257. The next prime is 21063281. The reversal of 21063265 is 56236012.

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 5349969 + 15713296 = 2313^2 + 3964^2 .

It is a cyclic number.

It is not a de Polignac number, because 21063265 - 2³ = 21063257 is a prime.

It is a super-2 number, since 2×21063265² = 887322264920450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2106322 + ... + 2106331.

It is an arithmetic number, because the mean of its divisors is an integer number (6318981).

Almost surely, 2^21063265 is an apocalyptic number.

It is an amenable number.

21063265 is a deficient number, since it is larger than the sum of its proper divisors (4212659).

21063265 is an equidigital number, since it uses as much as digits as its factorization.

21063265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4212658.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21063265 is about 4589.4732813254. The cubic root of 21063265 is about 276.1691928020.

Adding to 21063265 its reverse (56236012), we get a palindrome (77299277).

The spelling of 21063265 in words is "twenty-one million, sixty-three thousand, two hundred sixty-five".