21365265 has 8 divisors (see below), whose sum is σ = 34184448. Its totient is φ = 11394800.

The previous prime is 21365233. The next prime is 21365269. The reversal of 21365265 is 56256312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21365265 - 2⁵ = 21365233 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21365269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 712161 + ... + 712190.

It is an arithmetic number, because the mean of its divisors is an integer number (4273056).

Almost surely, 2^21365265 is an apocalyptic number.

It is an amenable number.

21365265 is a deficient number, since it is larger than the sum of its proper divisors (12819183).

21365265 is a wasteful number, since it uses less digits than its factorization.

21365265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424359.

The product of its digits is 10800, while the sum is 30.

The square root of 21365265 is about 4622.2575653029. The cubic root of 21365265 is about 277.4828168891.

The spelling of 21365265 in words is "twenty-one million, three hundred sixty-five thousand, two hundred sixty-five".