19966717 has 4 divisors (see below), whose sum is σ = 20506396. Its totient is φ = 19427040.

The previous prime is 19966711. The next prime is 19966747. The reversal of 19966717 is 71766991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15531481 + 4435236 = 3941^2 + 2106^2 .

It is a cyclic number.

It is not a de Polignac number, because 19966717 - 2¹¹ = 19964669 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 (19966711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 269784 + ... + 269857.

It is an arithmetic number, because the mean of its divisors is an integer number (5126599).

Almost surely, 2^19966717 is an apocalyptic number.

It is an amenable number.

19966717 is a deficient number, since it is larger than the sum of its proper divisors (539679).

19966717 is an equidigital number, since it uses as much as digits as its factorization.

19966717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 539678.

The product of its digits is 142884, while the sum is 46.

The square root of 19966717 is about 4468.4132530463. The cubic root of 19966717 is about 271.2911047875.

The spelling of 19966717 in words is "nineteen million, nine hundred sixty-six thousand, seven hundred seventeen".