21841865 has 8 divisors (see below), whose sum is σ = 26526528. Its totient is φ = 17262640.

The previous prime is 21841861. The next prime is 21841879. The reversal of 21841865 is 56814812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21841865 - 2² = 21841861 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21841861) 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 7 ways as a sum of consecutive naturals, for example, 25901 + ... + 26730.

It is an arithmetic number, because the mean of its divisors is an integer number (3315816).

Almost surely, 2^21841865 is an apocalyptic number.

It is an amenable number.

21841865 is a deficient number, since it is larger than the sum of its proper divisors (4684663).

21841865 is an equidigital number, since it uses as much as digits as its factorization.

21841865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52719.

The product of its digits is 15360, while the sum is 35.

The square root of 21841865 is about 4673.5281105392. The cubic root of 21841865 is about 279.5309536541.

The spelling of 21841865 in words is "twenty-one million, eight hundred forty-one thousand, eight hundred sixty-five".