685780786 has 4 divisors (see below), whose sum is σ = 1028671182. Its totient is φ = 342890392.

The previous prime is 685780783. The next prime is 685780817. The reversal of 685780786 is 687087586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 687087586 = 2 ⋅343543793.

It can be written as a sum of positive squares in only one way, i.e., 359292025 + 326488761 = 18955^2 + 18069^2 .

It is not an unprimeable number, because it can be changed into a prime (685780783) 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 as a sum of consecutive naturals, namely, 171445195 + ... + 171445198.

Almost surely, 2^685780786 is an apocalyptic number.

685780786 is a deficient number, since it is larger than the sum of its proper divisors (342890396).

685780786 is a wasteful number, since it uses less digits than its factorization.

685780786 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342890395.

The product of its (nonzero) digits is 4515840, while the sum is 55.

The square root of 685780786 is about 26187.4165583396. The cubic root of 685780786 is about 881.8507819476.

The spelling of 685780786 in words is "six hundred eighty-five million, seven hundred eighty thousand, seven hundred eighty-six".