1681659889985 has 8 divisors (see below), whose sum is σ = 2018853903336. Its totient is φ = 1344753221760.

The previous prime is 1681659889979. The next prime is 1681659889991. The reversal of 1681659889985 is 5899889561861.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1681659889979) and next prime (1681659889991).

It can be written as a sum of positive squares in 4 ways, for example, as 488968743169 + 1192691146816 = 699263^2 + 1092104^2 .

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

It is not a de Polignac number, because 1681659889985 - 2⁴ = 1681659889969 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 71823404 + ... + 71846813.

It is an arithmetic number, because the mean of its divisors is an integer number (252356737917).

Almost surely, 2^{1681659889985} is an apocalyptic number.

It is an amenable number.

1681659889985 is a deficient number, since it is larger than the sum of its proper divisors (337194013351).

1681659889985 is a wasteful number, since it uses less digits than its factorization.

1681659889985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143672563.

The product of its digits is 2687385600, while the sum is 83.

The spelling of 1681659889985 in words is "one trillion, six hundred eighty-one billion, six hundred fifty-nine million, eight hundred eighty-nine thousand, nine hundred eighty-five".