21114865 has 4 divisors (see below), whose sum is σ = 25337844. Its totient is φ = 16891888.

The previous prime is 21114853. The next prime is 21114869. The reversal of 21114865 is 56841112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13808656 + 7306209 = 3716^2 + 2703^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21114865 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21114869) 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 3 ways as a sum of consecutive naturals, for example, 2111482 + ... + 2111491.

It is an arithmetic number, because the mean of its divisors is an integer number (6334461).

Almost surely, 2^21114865 is an apocalyptic number.

It is an amenable number.

21114865 is a deficient number, since it is larger than the sum of its proper divisors (4222979).

21114865 is an equidigital number, since it uses as much as digits as its factorization.

21114865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4222978.

The product of its digits is 1920, while the sum is 28.

The square root of 21114865 is about 4595.0914027906. The cubic root of 21114865 is about 276.3945252235.

Adding to 21114865 its reverse (56841112), we get a palindrome (77955977).

The spelling of 21114865 in words is "twenty-one million, one hundred fourteen thousand, eight hundred sixty-five".