687447749 has 8 divisors (see below), whose sum is σ = 696309600. Its totient is φ = 678599856.

The previous prime is 687447743. The next prime is 687447767. The reversal of 687447749 is 947744786.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-687447749 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 687447694 and 687447703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687447743) 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, 125894 + ... + 131240.

It is an arithmetic number, because the mean of its divisors is an integer number (87038700).

Almost surely, 2^687447749 is an apocalyptic number.

It is an amenable number.

687447749 is a deficient number, since it is larger than the sum of its proper divisors (8861851).

687447749 is a wasteful number, since it uses less digits than its factorization.

687447749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6979.

The product of its digits is 9483264, while the sum is 56.

The square root of 687447749 is about 26219.2247978463. The cubic root of 687447749 is about 882.5647239643.

The spelling of 687447749 in words is "six hundred eighty-seven million, four hundred forty-seven thousand, seven hundred forty-nine".