840681 has 12 divisors (see below), whose sum is σ = 1256580. Its totient is φ = 540960.

The previous prime is 840661. The next prime is 840683. The reversal of 840681 is 186048.

It can be written as a sum of positive squares in 2 ways, for example, as 549081 + 291600 = 741^2 + 540^2 .

It is not a de Polignac number, because 840681 - 2¹¹ = 838633 is a prime.

It is a super-2 number, since 2×840681² = 1413489087522, which contains 22 as substring.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 840681.

It is not an unprimeable number, because it can be changed into a prime (840683) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1350 + ... + 1871.

It is an arithmetic number, because the mean of its divisors is an integer number (104715).

2⁸⁴⁰⁶⁸¹ is an apocalyptic number.

It is an amenable number.

840681 is a deficient number, since it is larger than the sum of its proper divisors (415899).

840681 is a wasteful number, since it uses less digits than its factorization.

840681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3256 (or 3253 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 840681 is about 916.8865796815. The cubic root of 840681 is about 94.3793707316.

It can be divided in two parts, 840 and 681, that added together give a square (1521 = 39²).

The spelling of 840681 in words is "eight hundred forty thousand, six hundred eighty-one".