689479661 has 4 divisors (see below), whose sum is σ = 742516572. Its totient is φ = 636442752.

The previous prime is 689479603. The next prime is 689479729. The reversal of 689479661 is 166974986.

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 449694436 + 239785225 = 21206^2 + 15485^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-689479661 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 689479597 and 689479606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (689479601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26518436 + ... + 26518461.

It is an arithmetic number, because the mean of its divisors is an integer number (185629143).

Almost surely, 2^689479661 is an apocalyptic number.

It is an amenable number.

689479661 is a deficient number, since it is larger than the sum of its proper divisors (53036911).

689479661 is a wasteful number, since it uses less digits than its factorization.

689479661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53036910.

The product of its digits is 3919104, while the sum is 56.

The square root of 689479661 is about 26257.9447215505. The cubic root of 689479661 is about 883.4334105513.

The spelling of 689479661 in words is "six hundred eighty-nine million, four hundred seventy-nine thousand, six hundred sixty-one".