781085 has 4 divisors (see below), whose sum is σ = 937308. Its totient is φ = 624864.

The previous prime is 781069. The next prime is 781087. The reversal of 781085 is 580187.

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 2 ways, for example, as 198916 + 582169 = 446^2 + 763^2 .

It is a cyclic number.

It is not a de Polignac number, because 781085 - 2⁴ = 781069 is a prime.

It is a super-2 number, since 2×781085² = 1220187554450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 781085.

It is not an unprimeable number, because it can be changed into a prime (781087) 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 in 3 ways as a sum of consecutive naturals, for example, 78104 + ... + 78113.

It is an arithmetic number, because the mean of its divisors is an integer number (234327).

2⁷⁸¹⁰⁸⁵ is an apocalyptic number.

It is an amenable number.

781085 is a deficient number, since it is larger than the sum of its proper divisors (156223).

781085 is a wasteful number, since it uses less digits than its factorization.

781085 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156222.

The product of its (nonzero) digits is 2240, while the sum is 29.

The square root of 781085 is about 883.7901334593. The cubic root of 781085 is about 92.0943031141.

The spelling of 781085 in words is "seven hundred eighty-one thousand, eighty-five".