1681686625 has 8 divisors (see below), whose sum is σ = 2098745064. Its totient is φ = 1345349200.

The previous prime is 1681686623. The next prime is 1681686647. The reversal of 1681686625 is 5266861861.

It can be written as a sum of positive squares in 4 ways, for example, as 42732369 + 1638954256 = 6537^2 + 40484^2 .

It is not a de Polignac number, because 1681686625 - 2¹ = 1681686623 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681686623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6726622 + ... + 6726871.

It is an arithmetic number, because the mean of its divisors is an integer number (262343133).

Almost surely, 2^1681686625 is an apocalyptic number.

It is an amenable number.

1681686625 is a deficient number, since it is larger than the sum of its proper divisors (417058439).

1681686625 is an equidigital number, since it uses as much as digits as its factorization.

1681686625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13453508 (or 13453498 counting only the distinct ones).

The product of its digits is 829440, while the sum is 49.

The square root of 1681686625 is about 41008.3726207222. The cubic root of 1681686625 is about 1189.1820815976.

The spelling of 1681686625 in words is "one billion, six hundred eighty-one million, six hundred eighty-six thousand, six hundred twenty-five".