21732865 has 32 divisors (see below), whose sum is σ = 34237440. Its totient is φ = 12830400.

The previous prime is 21732863. The next prime is 21732869. The reversal of 21732865 is 56823712.

It is a happy number.

It is not a de Polignac number, because 21732865 - 2¹ = 21732863 is a prime.

It is a super-2 number, since 2×21732865² = 944634842216450, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21732865.

It is not an unprimeable number, because it can be changed into a prime (21732863) 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 31 ways as a sum of consecutive naturals, for example, 5830 + ... + 8800.

It is an arithmetic number, because the mean of its divisors is an integer number (1069920).

Almost surely, 2^21732865 is an apocalyptic number.

It is an amenable number.

21732865 is a deficient number, since it is larger than the sum of its proper divisors (12504575).

21732865 is a wasteful number, since it uses less digits than its factorization.

21732865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3013.

The product of its digits is 20160, while the sum is 34.

The square root of 21732865 is about 4661.8520997561. The cubic root of 21732865 is about 279.0651860550.

The spelling of 21732865 in words is "twenty-one million, seven hundred thirty-two thousand, eight hundred sixty-five".