687913 has 4 divisors (see below), whose sum is σ = 689920. Its totient is φ = 685908.

The previous prime is 687901. The next prime is 687917. The reversal of 687913 is 319786.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 687913 - 2¹⁷ = 556841 is a prime.

It is a Duffinian number.

687913 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (687917) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 345 + ... + 1222.

It is an arithmetic number, because the mean of its divisors is an integer number (172480).

2⁶⁸⁷⁹¹³ is an apocalyptic number.

It is an amenable number.

687913 is a deficient number, since it is larger than the sum of its proper divisors (2007).

687913 is a wasteful number, since it uses less digits than its factorization.

687913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2006.

The product of its digits is 9072, while the sum is 34.

The square root of 687913 is about 829.4052085682. The cubic root of 687913 is about 88.2763779831.

It can be divided in two parts, 687 and 913, that added together give a square (1600 = 40²).

The spelling of 687913 in words is "six hundred eighty-seven thousand, nine hundred thirteen".