689945 has 8 divisors (see below), whose sum is σ = 876744. Its totient is φ = 519424.

The previous prime is 689929. The next prime is 689951. The reversal of 689945 is 549986.

It can be written as a sum of positive squares in 4 ways, for example, as 290521 + 399424 = 539^2 + 632^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 689945 - 2⁴ = 689929 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 15.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3974 + ... + 4143.

It is an arithmetic number, because the mean of its divisors is an integer number (109593).

2⁶⁸⁹⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

689945 is a deficient number, since it is larger than the sum of its proper divisors (186799).

689945 is a wasteful number, since it uses less digits than its factorization.

689945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8139.

The product of its digits is 77760, while the sum is 41.

The square root of 689945 is about 830.6292795225. The cubic root of 689945 is about 88.3632112845.

Adding to 689945 its sum of digits (41), we get a palindrome (689986).

The spelling of 689945 in words is "six hundred eighty-nine thousand, nine hundred forty-five".