21703813 has 8 divisors (see below), whose sum is σ = 22470656. Its totient is φ = 20941200.

The previous prime is 21703783. The next prime is 21703817. The reversal of 21703813 is 31830712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21703813 is a prime.

It is a Duffinian number.

21703813 is a modest number, since divided by 3813 gives 217 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21703817) 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 7 ways as a sum of consecutive naturals, for example, 12220 + ... + 13882.

It is an arithmetic number, because the mean of its divisors is an integer number (2808832).

Almost surely, 2^21703813 is an apocalyptic number.

It is an amenable number.

21703813 is a deficient number, since it is larger than the sum of its proper divisors (766843).

21703813 is a wasteful number, since it uses less digits than its factorization.

21703813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 21703813 is about 4658.7351287662. The cubic root of 21703813 is about 278.9407812719.

The spelling of 21703813 in words is "twenty-one million, seven hundred three thousand, eight hundred thirteen".