1688629725 has 18 divisors (see below), whose sum is σ = 3024523866. Its totient is φ = 900602400.

The previous prime is 1688629721. The next prime is 1688629727. The reversal of 1688629725 is 5279268861.

1688629725 is a `hidden beast` number, since 1 + 6 + 8 + 8 + 629 + 7 + 2 + 5 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 29615364 + 1659014361 = 5442^2 + 40731^2 .

It is not a de Polignac number, because 1688629725 - 2² = 1688629721 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1688629721) by changing a digit.

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 17 ways as a sum of consecutive naturals, for example, 3752286 + ... + 3752735.

Almost surely, 2^1688629725 is an apocalyptic number.

1688629725 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1688629725 is a deficient number, since it is larger than the sum of its proper divisors (1335894141).

1688629725 is a wasteful number, since it uses less digits than its factorization.

1688629725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7505037 (or 7505029 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The square root of 1688629725 is about 41092.9400870758. The cubic root of 1688629725 is about 1190.8164077334.

The spelling of 1688629725 in words is "one billion, six hundred eighty-eight million, six hundred twenty-nine thousand, seven hundred twenty-five".