685781031 has 8 divisors (see below), whose sum is σ = 984711280. Its totient is φ = 422019072.

The previous prime is 685781029. The next prime is 685781059. The reversal of 685781031 is 130187586.

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

It is not a de Polignac number, because 685781031 - 2¹ = 685781029 is a prime.

It is a super-2 number, since 2×685781031² = 940591244958845922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 17584129 = 685781031 / (6 + 8 + 5 + 7 + 8 + 1 + 0 + 3 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685788031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8792026 + ... + 8792103.

It is an arithmetic number, because the mean of its divisors is an integer number (123088910).

Almost surely, 2^685781031 is an apocalyptic number.

685781031 is a deficient number, since it is larger than the sum of its proper divisors (298930249).

685781031 is a wasteful number, since it uses less digits than its factorization.

685781031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17584145.

The product of its (nonzero) digits is 40320, while the sum is 39.

The square root of 685781031 is about 26187.4212361584. The cubic root of 685781031 is about 881.8508869634.

The spelling of 685781031 in words is "six hundred eighty-five million, seven hundred eighty-one thousand, thirty-one".