21236265 has 24 divisors (see below), whose sum is σ = 38081160. Its totient is φ = 10934784.

The previous prime is 21236263. The next prime is 21236273. The reversal of 21236265 is 56263212.

It can be written as a sum of positive squares in 4 ways, for example, as 7420176 + 13816089 = 2724^2 + 3717^2 .

It is not a de Polignac number, because 21236265 - 2¹ = 21236263 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21236263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6832 + ... + 9441.

It is an arithmetic number, because the mean of its divisors is an integer number (1586715).

Almost surely, 2^21236265 is an apocalyptic number.

It is an amenable number.

21236265 is a deficient number, since it is larger than the sum of its proper divisors (16844895).

21236265 is a wasteful number, since it uses less digits than its factorization.

21236265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16313 (or 16310 counting only the distinct ones).

The product of its digits is 4320, while the sum is 27.

The square root of 21236265 is about 4608.2822179203. The cubic root of 21236265 is about 276.9232237357.

Adding to 21236265 its reverse (56263212), we get a palindrome (77499477).

The spelling of 21236265 in words is "twenty-one million, two hundred thirty-six thousand, two hundred sixty-five".