21032565 has 16 divisors (see below), whose sum is σ = 34080000. Its totient is φ = 11074752.

The previous prime is 21032537. The next prime is 21032567. The reversal of 21032565 is 56523012.

It is not a de Polignac number, because 21032565 - 2⁵ = 21032533 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21032567) 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, 7690 + ... + 10059.

It is an arithmetic number, because the mean of its divisors is an integer number (2130000).

Almost surely, 2^21032565 is an apocalyptic number.

It is an amenable number.

21032565 is a deficient number, since it is larger than the sum of its proper divisors (13047435).

21032565 is a wasteful number, since it uses less digits than its factorization.

21032565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17836.

The product of its (nonzero) digits is 1800, while the sum is 24.

The square root of 21032565 is about 4586.1274513472. The cubic root of 21032565 is about 276.0349540902.

Adding to 21032565 its reverse (56523012), we get a palindrome (77555577).

The spelling of 21032565 in words is "twenty-one million, thirty-two thousand, five hundred sixty-five".