687681517 has 8 divisors (see below), whose sum is σ = 691467840. Its totient is φ = 683904000.

The previous prime is 687681503. The next prime is 687681523. The reversal of 687681517 is 715186786.

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

It is a cyclic number.

It is not a de Polignac number, because 687681517 - 2¹¹ = 687679469 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 (687681217) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204909 + ... + 208237.

It is an arithmetic number, because the mean of its divisors is an integer number (86433480).

Almost surely, 2^687681517 is an apocalyptic number.

It is an amenable number.

687681517 is a deficient number, since it is larger than the sum of its proper divisors (3786323).

687681517 is a wasteful number, since it uses less digits than its factorization.

687681517 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4403.

The product of its digits is 564480, while the sum is 49.

The square root of 687681517 is about 26223.6823691868. The cubic root of 687681517 is about 882.6647519345.

The spelling of 687681517 in words is "six hundred eighty-seven million, six hundred eighty-one thousand, five hundred seventeen".