689989 has 4 divisors (see below), whose sum is σ = 706860. Its totient is φ = 673120.

The previous prime is 689987. The next prime is 690037. The reversal of 689989 is 989986.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 22500 + 667489 = 150^2 + 817^2 .

It is a cyclic number.

It is not a de Polignac number, because 689989 - 2¹ = 689987 is a prime.

It is a Duffinian number.

689989 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (689981) 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, 8374 + ... + 8455.

It is an arithmetic number, because the mean of its divisors is an integer number (176715).

2⁶⁸⁹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

689989 is a deficient number, since it is larger than the sum of its proper divisors (16871).

689989 is a wasteful number, since it uses less digits than its factorization.

689989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16870.

The product of its digits is 279936, while the sum is 49.

The square root of 689989 is about 830.6557650435. The cubic root of 689989 is about 88.3650896461.

The spelling of 689989 in words is "six hundred eighty-nine thousand, nine hundred eighty-nine".