687511 has 4 divisors (see below), whose sum is σ = 750024. Its totient is φ = 625000.

The previous prime is 687499. The next prime is 687517. The reversal of 687511 is 115786.

687511 = 336² + 337² + ... + 341².

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a 7-Lehmer number, since φ(687511) divides (687511-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 687511 - 2⁷ = 687383 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 687511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 31240 + ... + 31261.

It is an arithmetic number, because the mean of its divisors is an integer number (187506).

2⁶⁸⁷⁵¹¹ is an apocalyptic number.

687511 is a deficient number, since it is larger than the sum of its proper divisors (62513).

687511 is a wasteful number, since it uses less digits than its factorization.

687511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62512.

The product of its digits is 1680, while the sum is 28.

The square root of 687511 is about 829.1628308119. The cubic root of 687511 is about 88.2591790938.

It can be divided in two parts, 6875 and 11, that multiplied together give a square (75625 = 275²).

The spelling of 687511 in words is "six hundred eighty-seven thousand, five hundred eleven".