685561810 has 16 divisors (see below), whose sum is σ = 1234690776. Its totient is φ = 274073728.

The previous prime is 685561741. The next prime is 685561817. The reversal of 685561810 is 18165586.

It can be written as a sum of positive squares in 4 ways, for example, as 598829841 + 86731969 = 24471^2 + 9313^2 .

It is a super-2 number, since 2×685561810² = 939989990660952200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (685561817) 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 7 ways as a sum of consecutive naturals, for example, 1212 + ... + 37048.

Almost surely, 2^685561810 is an apocalyptic number.

685561810 is a deficient number, since it is larger than the sum of its proper divisors (549128966).

685561810 is a wasteful number, since it uses less digits than its factorization.

685561810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37757.

The product of its (nonzero) digits is 57600, while the sum is 40.

The square root of 685561810 is about 26183.2352851973. The cubic root of 685561810 is about 881.7569109820.

The spelling of 685561810 in words is "six hundred eighty-five million, five hundred sixty-one thousand, eight hundred ten".