21707917 has 8 divisors (see below), whose sum is σ = 27064512. Its totient is φ = 16915200.

The previous prime is 21707909. The next prime is 21707927. The reversal of 21707917 is 71970712.

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

It is a cyclic number.

It is not a de Polignac number, because 21707917 - 2³ = 21707909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21707927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 140884 + ... + 141037.

It is an arithmetic number, because the mean of its divisors is an integer number (3383064).

Almost surely, 2^21707917 is an apocalyptic number.

It is an amenable number.

21707917 is a deficient number, since it is larger than the sum of its proper divisors (5356595).

21707917 is a wasteful number, since it uses less digits than its factorization.

21707917 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281939.

The product of its (nonzero) digits is 6174, while the sum is 34.

The square root of 21707917 is about 4659.1755708494. The cubic root of 21707917 is about 278.9583619127.

The spelling of 21707917 in words is "twenty-one million, seven hundred seven thousand, nine hundred seventeen".