21452565 has 16 divisors (see below), whose sum is σ = 34574400. Its totient is φ = 11357952.

The previous prime is 21452549. The next prime is 21452567. The reversal of 21452565 is 56525412.

It is not a de Polignac number, because 21452565 - 2⁴ = 21452549 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21452567) 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, 3060 + ... + 7229.

It is an arithmetic number, because the mean of its divisors is an integer number (2160900).

Almost surely, 2^21452565 is an apocalyptic number.

It is an amenable number.

21452565 is a deficient number, since it is larger than the sum of its proper divisors (13121835).

21452565 is a wasteful number, since it uses less digits than its factorization.

21452565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10436.

The product of its digits is 12000, while the sum is 30.

The square root of 21452565 is about 4631.6913757287. The cubic root of 21452565 is about 277.8602415018.

Adding to 21452565 its reverse (56525412), we get a palindrome (77977977).

The spelling of 21452565 in words is "twenty-one million, four hundred fifty-two thousand, five hundred sixty-five".