19716985 has 4 divisors (see below), whose sum is σ = 23660388. Its totient is φ = 15773584.

The previous prime is 19716959. The next prime is 19716989. The reversal of 19716985 is 58961791.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58961791 = 7 ⋅8423113.

It can be written as a sum of positive squares in 2 ways, for example, as 2585664 + 17131321 = 1608^2 + 4139^2 .

It is a cyclic number.

It is not a de Polignac number, because 19716985 - 2⁵ = 19716953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19716989) 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, 1971694 + ... + 1971703.

It is an arithmetic number, because the mean of its divisors is an integer number (5915097).

Almost surely, 2^19716985 is an apocalyptic number.

It is an amenable number.

19716985 is a deficient number, since it is larger than the sum of its proper divisors (3943403).

19716985 is an equidigital number, since it uses as much as digits as its factorization.

19716985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3943402.

The product of its digits is 136080, while the sum is 46.

The square root of 19716985 is about 4440.3811773315. The cubic root of 19716985 is about 270.1553061685.

The spelling of 19716985 in words is "nineteen million, seven hundred sixteen thousand, nine hundred eighty-five".