21706735 has 16 divisors (see below), whose sum is σ = 26604864. Its totient is φ = 16998912.

The previous prime is 21706717. The next prime is 21706777. The reversal of 21706735 is 53760712.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21706735 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21706697 and 21706706.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58009 + ... + 58381.

It is an arithmetic number, because the mean of its divisors is an integer number (1662804).

Almost surely, 2^21706735 is an apocalyptic number.

21706735 is a deficient number, since it is larger than the sum of its proper divisors (4898129).

21706735 is a wasteful number, since it uses less digits than its factorization.

21706735 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 594.

The product of its (nonzero) digits is 8820, while the sum is 31.

The square root of 21706735 is about 4659.0487226471. The cubic root of 21706735 is about 278.9532987097.

The spelling of 21706735 in words is "twenty-one million, seven hundred six thousand, seven hundred thirty-five".