686499890 has 24 divisors (see below), whose sum is σ = 1279795140. Its totient is φ = 265127744.

The previous prime is 686499881. The next prime is 686499893. The reversal of 686499890 is 98994686.

It can be written as a sum of positive squares in 6 ways, for example, as 410508121 + 275991769 = 20261^2 + 16613^2 .

It is not an unprimeable number, because it can be changed into a prime (686499893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32405 + ... + 49224.

Almost surely, 2^686499890 is an apocalyptic number.

686499890 is a deficient number, since it is larger than the sum of its proper divisors (593295250).

686499890 is a wasteful number, since it uses less digits than its factorization.

686499890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81694 (or 81665 counting only the distinct ones).

The product of its (nonzero) digits is 6718464, while the sum is 59.

The square root of 686499890 is about 26201.1429140028. The cubic root of 686499890 is about 882.1589080595.

The spelling of 686499890 in words is "six hundred eighty-six million, four hundred ninety-nine thousand, eight hundred ninety".