689689 has 24 divisors (see below), whose sum is σ = 948672. Its totient is φ = 486720.

The previous prime is 689641. The next prime is 689693. The reversal of 689689 is 986986.

689689 = 38² + 39² + ... + 128².

It is a happy number.

It is not a de Polignac number, because 689689 - 2⁷ = 689561 is a prime.

689689 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (689629) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12987 + ... + 13039.

It is an arithmetic number, because the mean of its divisors is an integer number (39528).

2⁶⁸⁹⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

689689 is a deficient number, since it is larger than the sum of its proper divisors (258983).

689689 is a wasteful number, since it uses less digits than its factorization.

689689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97 (or 84 counting only the distinct ones).

The product of its digits is 186624, while the sum is 46.

The square root of 689689 is about 830.4751651916. The cubic root of 689689 is about 88.3522810507.

It can be divided in two parts, 689 and 689, that added together give a triangular number (1378 = T₅₂).

The spelling of 689689 in words is "six hundred eighty-nine thousand, six hundred eighty-nine".