21826865 has 8 divisors (see below), whose sum is σ = 26220840. Its totient is φ = 17442432.

The previous prime is 21826859. The next prime is 21826867. The reversal of 21826865 is 56862812.

It can be written as a sum of positive squares in 4 ways, for example, as 1024144 + 20802721 = 1012^2 + 4561^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21826865 - 2²² = 17632561 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21826867) 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 7 ways as a sum of consecutive naturals, for example, 4421 + ... + 7949.

It is an arithmetic number, because the mean of its divisors is an integer number (3277605).

Almost surely, 2^21826865 is an apocalyptic number.

It is an amenable number.

21826865 is a deficient number, since it is larger than the sum of its proper divisors (4393975).

21826865 is a wasteful number, since it uses less digits than its factorization.

21826865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4771.

The product of its digits is 46080, while the sum is 38.

The square root of 21826865 is about 4671.9230515924. The cubic root of 21826865 is about 279.4669492827.

The spelling of 21826865 in words is "twenty-one million, eight hundred twenty-six thousand, eight hundred sixty-five".