685367781 has 8 divisors (see below), whose sum is σ = 1044369984. Its totient is φ = 391638720.

The previous prime is 685367773. The next prime is 685367803. The reversal of 685367781 is 187763586.

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

It is not a de Polignac number, because 685367781 - 2³ = 685367773 is a prime.

It is a super-2 number, since 2×685367781² = 939457990465727922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685367281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16318260 + ... + 16318301.

It is an arithmetic number, because the mean of its divisors is an integer number (130546248).

Almost surely, 2^685367781 is an apocalyptic number.

It is an amenable number.

685367781 is a deficient number, since it is larger than the sum of its proper divisors (359002203).

685367781 is a wasteful number, since it uses less digits than its factorization.

685367781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32636571.

The product of its digits is 1693440, while the sum is 51.

The square root of 685367781 is about 26179.5298086119. The cubic root of 685367781 is about 881.6737176301.

The spelling of 685367781 in words is "six hundred eighty-five million, three hundred sixty-seven thousand, seven hundred eighty-one".