21648017 has 4 divisors (see below), whose sum is σ = 21657456. Its totient is φ = 21638580.

The previous prime is 21648001. The next prime is 21648047. The reversal of 21648017 is 71084612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21648017 - 2⁴ = 21648001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21648047) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1178 + ... + 6684.

It is an arithmetic number, because the mean of its divisors is an integer number (5414364).

Almost surely, 2^21648017 is an apocalyptic number.

It is an amenable number.

21648017 is a deficient number, since it is larger than the sum of its proper divisors (9439).

21648017 is an equidigital number, since it uses as much as digits as its factorization.

21648017 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9438.

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 21648017 is about 4652.7429544302. The cubic root of 21648017 is about 278.7015431867.

The spelling of 21648017 in words is "twenty-one million, six hundred forty-eight thousand, seventeen".