21272265 has 24 divisors (see below), whose sum is σ = 42139968. Its totient is φ = 9724320.

The previous prime is 21272213. The next prime is 21272269. The reversal of 21272265 is 56227212.

It is not a de Polignac number, because 21272265 - 2¹¹ = 21270217 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21272269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 33451 + ... + 34080.

It is an arithmetic number, because the mean of its divisors is an integer number (1755832).

Almost surely, 2^21272265 is an apocalyptic number.

It is an amenable number.

21272265 is a deficient number, since it is larger than the sum of its proper divisors (20867703).

21272265 is a wasteful number, since it uses less digits than its factorization.

21272265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 67549 (or 67546 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21272265 is about 4612.1865747170. The cubic root of 21272265 is about 277.0796167113.

Adding to 21272265 its reverse (56227212), we get a palindrome (77499477).

The spelling of 21272265 in words is "twenty-one million, two hundred seventy-two thousand, two hundred sixty-five".