21648741 has 4 divisors (see below), whose sum is σ = 28864992. Its totient is φ = 14432492.

The previous prime is 21648721. The next prime is 21648749. The reversal of 21648741 is 14784612.

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.

It is a cyclic number.

It is not a de Polignac number, because 21648741 - 2⁵ = 21648709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21648749) 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, 3608121 + ... + 3608126.

It is an arithmetic number, because the mean of its divisors is an integer number (7216248).

Almost surely, 2^21648741 is an apocalyptic number.

It is an amenable number.

21648741 is a deficient number, since it is larger than the sum of its proper divisors (7216251).

21648741 is an equidigital number, since it uses as much as digits as its factorization.

21648741 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7216250.

The product of its digits is 10752, while the sum is 33.

The square root of 21648741 is about 4652.8207573471. The cubic root of 21648741 is about 278.7046501328.

The spelling of 21648741 in words is "twenty-one million, six hundred forty-eight thousand, seven hundred forty-one".