685566890 has 8 divisors (see below), whose sum is σ = 1234020420. Its totient is φ = 274226752.

The previous prime is 685566883. The next prime is 685566899. The reversal of 685566890 is 98665586.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 654285241 + 31281649 = 25579^2 + 5593^2 .

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

It is not an unprimeable number, because it can be changed into a prime (685566899) 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, 34278335 + ... + 34278354.

Almost surely, 2^685566890 is an apocalyptic number.

685566890 is a deficient number, since it is larger than the sum of its proper divisors (548453530).

685566890 is a wasteful number, since it uses less digits than its factorization.

685566890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68556696.

The product of its (nonzero) digits is 3110400, while the sum is 53.

The square root of 685566890 is about 26183.3322936558. The cubic root of 685566890 is about 881.7590889106.

The spelling of 685566890 in words is "six hundred eighty-five million, five hundred sixty-six thousand, eight hundred ninety".