685235578 has 4 divisors (see below), whose sum is σ = 1027853370. Its totient is φ = 342617788.

The previous prime is 685235567. The next prime is 685235591. The reversal of 685235578 is 875532586.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 656538129 + 28697449 = 25623^2 + 5357^2 .

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171308893 + ... + 171308896.

Almost surely, 2^685235578 is an apocalyptic number.

685235578 is a deficient number, since it is larger than the sum of its proper divisors (342617792).

685235578 is a wasteful number, since it uses less digits than its factorization.

685235578 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342617791.

The product of its digits is 2016000, while the sum is 49.

The square root of 685235578 is about 26177.0047560832. The cubic root of 685235578 is about 881.6170242707.

The spelling of 685235578 in words is "six hundred eighty-five million, two hundred thirty-five thousand, five hundred seventy-eight".