687646 has 4 divisors (see below), whose sum is σ = 1031472. Its totient is φ = 343822.

The previous prime is 687641. The next prime is 687647. The reversal of 687646 is 646786.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171910 + ... + 171913.

It is an arithmetic number, because the mean of its divisors is an integer number (257868).

2⁶⁸⁷⁶⁴⁶ is an apocalyptic number.

687646 is a deficient number, since it is larger than the sum of its proper divisors (343826).

687646 is a wasteful number, since it uses less digits than its factorization.

687646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343825.

The product of its digits is 48384, while the sum is 37.

The square root of 687646 is about 829.2442342278. The cubic root of 687646 is about 88.2649555877.

The spelling of 687646 in words is "six hundred eighty-seven thousand, six hundred forty-six".