688994 has 4 divisors (see below), whose sum is σ = 1033494. Its totient is φ = 344496.

The previous prime is 688979. The next prime is 688999. The reversal of 688994 is 499886.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 499886 = 2 ⋅249943.

It can be written as a sum of positive squares in only one way, i.e., 508369 + 180625 = 713^2 + 425^2 .

It is not an unprimeable number, because it can be changed into a prime (688999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 172247 + ... + 172250.

2⁶⁸⁸⁹⁹⁴ is an apocalyptic number.

688994 is a deficient number, since it is larger than the sum of its proper divisors (344500).

688994 is a wasteful number, since it uses less digits than its factorization.

688994 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344499.

The product of its digits is 124416, while the sum is 44.

The square root of 688994 is about 830.0566245745. The cubic root of 688994 is about 88.3225935283.

The spelling of 688994 in words is "six hundred eighty-eight thousand, nine hundred ninety-four".