687945 has 8 divisors (see below), whose sum is σ = 1100736. Its totient is φ = 366896.

The previous prime is 687931. The next prime is 687949. The reversal of 687945 is 549786.

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 687945 - 2⁹ = 687433 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (687949) 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, 22917 + ... + 22946.

It is an arithmetic number, because the mean of its divisors is an integer number (137592).

2⁶⁸⁷⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

687945 is a deficient number, since it is larger than the sum of its proper divisors (412791).

687945 is a wasteful number, since it uses less digits than its factorization.

687945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45871.

The product of its digits is 60480, while the sum is 39.

The square root of 687945 is about 829.4244992765. The cubic root of 687945 is about 88.2777467610.

The spelling of 687945 in words is "six hundred eighty-seven thousand, nine hundred forty-five".