687256749 has 12 divisors (see below), whose sum is σ = 995569536. Its totient is φ = 456848712.

The previous prime is 687256741. The next prime is 687256753. The reversal of 687256749 is 947652786.

687256749 is a `hidden beast` number, since 6 + 8 + 72 + 567 + 4 + 9 = 666.

It is not a de Polignac number, because 687256749 - 2³ = 687256741 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 687256695 and 687256704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687256741) 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 11 ways as a sum of consecutive naturals, for example, 106909 + ... + 113154.

It is an arithmetic number, because the mean of its divisors is an integer number (82964128).

Almost surely, 2^687256749 is an apocalyptic number.

It is an amenable number.

687256749 is a deficient number, since it is larger than the sum of its proper divisors (308312787).

687256749 is a wasteful number, since it uses less digits than its factorization.

687256749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220416 (or 220413 counting only the distinct ones).

The product of its digits is 5080320, while the sum is 54.

The square root of 687256749 is about 26215.5821793070. The cubic root of 687256749 is about 882.4829793388.

The spelling of 687256749 in words is "six hundred eighty-seven million, two hundred fifty-six thousand, seven hundred forty-nine".