1687730725 has 6 divisors (see below), whose sum is σ = 2092786130. Its totient is φ = 1350184560.

The previous prime is 1687730669. The next prime is 1687730747. The reversal of 1687730725 is 5270377861.

It is a Cunningham number, because it is equal to 41082²+1.

It can be written as a sum of positive squares in 3 ways, for example, as 1 + 1687730724 = 1^2 + 41082^2 .

It is not a de Polignac number, because 1687730725 - 2²³ = 1679342117 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 33754590 + ... + 33754639.

Almost surely, 2^1687730725 is an apocalyptic number.

It is an amenable number.

1687730725 is a deficient number, since it is larger than the sum of its proper divisors (405055405).

1687730725 is an equidigital number, since it uses as much as digits as its factorization.

1687730725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67509239 (or 67509234 counting only the distinct ones).

The product of its (nonzero) digits is 493920, while the sum is 46.

The square root of 1687730725 is about 41082.0000121708. Note that the first 4 decimals coincide. The cubic root of 1687730725 is about 1190.6050462231.

The spelling of 1687730725 in words is "one billion, six hundred eighty-seven million, seven hundred thirty thousand, seven hundred twenty-five".