21386717 has 8 divisors (see below), whose sum is σ = 24135840. Its totient is φ = 18771760.

The previous prime is 21386713. The next prime is 21386747. The reversal of 21386717 is 71768312.

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 21386717 - 2² = 21386713 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 (21386713) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 33203 + ... + 33840.

It is an arithmetic number, because the mean of its divisors is an integer number (3016980).

Almost surely, 2^21386717 is an apocalyptic number.

It is an amenable number.

21386717 is a deficient number, since it is larger than the sum of its proper divisors (2749123).

21386717 is a wasteful number, since it uses less digits than its factorization.

21386717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67083.

The product of its digits is 14112, while the sum is 35.

The square root of 21386717 is about 4624.5774942150. The cubic root of 21386717 is about 277.5756555887.

The spelling of 21386717 in words is "twenty-one million, three hundred eighty-six thousand, seven hundred seventeen".