687749709 has 8 divisors (see below), whose sum is σ = 919459552. Its totient is φ = 457269840.

The previous prime is 687749687. The next prime is 687749719. The reversal of 687749709 is 907947786.

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

It is not a de Polignac number, because 687749709 - 2¹³ = 687741517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687749719) 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 7 ways as a sum of consecutive naturals, for example, 306187 + ... + 308424.

It is an arithmetic number, because the mean of its divisors is an integer number (114932444).

Almost surely, 2^687749709 is an apocalyptic number.

It is an amenable number.

687749709 is a deficient number, since it is larger than the sum of its proper divisors (231709843).

687749709 is a wasteful number, since it uses less digits than its factorization.

687749709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614987.

The product of its (nonzero) digits is 5334336, while the sum is 57.

The square root of 687749709 is about 26224.9825357425. The cubic root of 687749709 is about 882.6939266246.

The spelling of 687749709 in words is "six hundred eighty-seven million, seven hundred forty-nine thousand, seven hundred nine".