688987 has 4 divisors (see below), whose sum is σ = 742000. Its totient is φ = 635976.

The previous prime is 688979. The next prime is 688999. The reversal of 688987 is 789886.

688987 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 789886 = 2 ⋅394943.

It is a cyclic number.

It is not a de Polignac number, because 688987 - 2³ = 688979 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688907) 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, 26487 + ... + 26512.

It is an arithmetic number, because the mean of its divisors is an integer number (185500).

2⁶⁸⁸⁹⁸⁷ is an apocalyptic number.

688987 is a deficient number, since it is larger than the sum of its proper divisors (53013).

688987 is a wasteful number, since it uses less digits than its factorization.

688987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53012.

The product of its digits is 193536, while the sum is 46.

The square root of 688987 is about 830.0524079840. The cubic root of 688987 is about 88.3222944158.

It can be divided in two parts, 68 and 8987, that multiplied together give a palindrome (611116).

The spelling of 688987 in words is "six hundred eighty-eight thousand, nine hundred eighty-seven".