687621 has 16 divisors (see below), whose sum is σ = 1018368. Its totient is φ = 409200.

The previous prime is 687593. The next prime is 687623. The reversal of 687621 is 126786.

It is a happy number.

687621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 687621 - 2⁹ = 687109 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687623) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2056 + ... + 2366.

It is an arithmetic number, because the mean of its divisors is an integer number (63648).

2⁶⁸⁷⁶²¹ is an apocalyptic number.

It is an amenable number.

687621 is a deficient number, since it is larger than the sum of its proper divisors (330747).

687621 is a wasteful number, since it uses less digits than its factorization.

687621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392.

The product of its digits is 4032, while the sum is 30.

The square root of 687621 is about 829.2291601240. The cubic root of 687621 is about 88.2638859236.

The spelling of 687621 in words is "six hundred eighty-seven thousand, six hundred twenty-one".