689640 has 64 divisors (see below), whose sum is σ = 2367360. Its totient is φ = 157440.

The previous prime is 689629. The next prime is 689641. The reversal of 689640 is 46986.

689640 = 16² + 17² + ... + 127².

It is a nialpdrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (689641) by changing a digit.

689640 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 430 + ... + 1250.

It is an arithmetic number, because the mean of its divisors is an integer number (36990).

2⁶⁸⁹⁶⁴⁰ is an apocalyptic number.

689640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 689640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1183680).

689640 is an abundant number, since it is smaller than the sum of its proper divisors (1677720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

689640 is a wasteful number, since it uses less digits than its factorization.

689640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 842 (or 838 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 689640 is about 830.4456634844. The cubic root of 689640 is about 88.3501886272.

The spelling of 689640 in words is "six hundred eighty-nine thousand, six hundred forty".