21241817 has 8 divisors (see below), whose sum is σ = 21714696. Its totient is φ = 20771712.

The previous prime is 21241799. The next prime is 21241819. The reversal of 21241817 is 71814212.

It can be written as a sum of positive squares in 4 ways, for example, as 13039321 + 8202496 = 3611^2 + 2864^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21241817 is a prime.

It is a super-2 number, since 2×21241817² = 902429578922978, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21241819) 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, 23783 + ... + 24659.

It is an arithmetic number, because the mean of its divisors is an integer number (2714337).

Almost surely, 2^21241817 is an apocalyptic number.

It is an amenable number.

21241817 is a deficient number, since it is larger than the sum of its proper divisors (472879).

21241817 is an equidigital number, since it uses as much as digits as its factorization.

21241817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1387.

The product of its digits is 896, while the sum is 26.

The square root of 21241817 is about 4608.8845722148. The cubic root of 21241817 is about 276.9473545291.

The spelling of 21241817 in words is "twenty-one million, two hundred forty-one thousand, eight hundred seventeen".