21244865 has 8 divisors (see below), whose sum is σ = 25525800. Its totient is φ = 16974592.

The previous prime is 21244859. The next prime is 21244871. The reversal of 21244865 is 56844212.

It is an interprime number because it is at equal distance from previous prime (21244859) and next prime (21244871).

It can be written as a sum of positive squares in 4 ways, for example, as 1495729 + 19749136 = 1223^2 + 4444^2 .

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 21244865 - 2⁸ = 21244609 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2711 + ... + 7059.

It is an arithmetic number, because the mean of its divisors is an integer number (3190725).

Almost surely, 2^21244865 is an apocalyptic number.

It is an amenable number.

21244865 is a deficient number, since it is larger than the sum of its proper divisors (4280935).

21244865 is an equidigital number, since it uses as much as digits as its factorization.

21244865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5331.

The product of its digits is 15360, while the sum is 32.

The square root of 21244865 is about 4609.2152260445. The cubic root of 21244865 is about 276.9606003383.

The spelling of 21244865 in words is "twenty-one million, two hundred forty-four thousand, eight hundred sixty-five".