19660671685 has 16 divisors (see below), whose sum is σ = 24444904176. Its totient is φ = 15167996928.

The previous prime is 19660671677. The next prime is 19660671703. The reversal of 19660671685 is 58617606691.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 47789569 + 19612882116 = 6913^2 + 140046^2 .

It is a cyclic number.

It is not a de Polignac number, because 19660671685 - 2³ = 19660671677 is a prime.

It is a super-2 number, since 2×19660671685² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 449334 + ... + 491143.

It is an arithmetic number, because the mean of its divisors is an integer number (1527806511).

Almost surely, 2^19660671685 is an apocalyptic number.

It is an amenable number.

19660671685 is a deficient number, since it is larger than the sum of its proper divisors (4784232491).

19660671685 is a wasteful number, since it uses less digits than its factorization.

19660671685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 940632.

The product of its (nonzero) digits is 3265920, while the sum is 55.

The spelling of 19660671685 in words is "nineteen billion, six hundred sixty million, six hundred seventy-one thousand, six hundred eighty-five".