21329265 has 16 divisors (see below), whose sum is σ = 34187328. Its totient is φ = 11355456.

The previous prime is 21329263. The next prime is 21329299. The reversal of 21329265 is 56292312.

It is not a de Polignac number, because 21329265 - 2¹ = 21329263 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21329263) 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 15 ways as a sum of consecutive naturals, for example, 11962 + ... + 13628.

It is an arithmetic number, because the mean of its divisors is an integer number (2136708).

Almost surely, 2^21329265 is an apocalyptic number.

It is an amenable number.

21329265 is a deficient number, since it is larger than the sum of its proper divisors (12858063).

21329265 is a wasteful number, since it uses less digits than its factorization.

21329265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2528.

The product of its digits is 6480, while the sum is 30.

The square root of 21329265 is about 4618.3617225159. The cubic root of 21329265 is about 277.3268784645.

The spelling of 21329265 in words is "twenty-one million, three hundred twenty-nine thousand, two hundred sixty-five".