21705741 has 12 divisors (see below), whose sum is σ = 31487040. Its totient is φ = 14408520.

The previous prime is 21705737. The next prime is 21705743. The reversal of 21705741 is 14750712.

21705741 is a `hidden beast` number, since 21 + 70 + 574 + 1 = 666.

It is not a de Polignac number, because 21705741 - 2² = 21705737 is a prime.

It is a super-2 number, since 2×21705741² = 942278384718162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21705743) 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 11 ways as a sum of consecutive naturals, for example, 2895 + ... + 7196.

It is an arithmetic number, because the mean of its divisors is an integer number (2623920).

Almost surely, 2^21705741 is an apocalyptic number.

It is an amenable number.

21705741 is a deficient number, since it is larger than the sum of its proper divisors (9781299).

21705741 is a wasteful number, since it uses less digits than its factorization.

21705741 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10336 (or 10333 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21705741 is about 4658.9420472893. The cubic root of 21705741 is about 278.9490406794.

The spelling of 21705741 in words is "twenty-one million, seven hundred five thousand, seven hundred forty-one".