840605 has 8 divisors (see below), whose sum is σ = 1020600. Its totient is φ = 664576.

The previous prime is 840601. The next prime is 840611. The reversal of 840605 is 506048.

It can be written as a sum of positive squares in 4 ways, for example, as 17956 + 822649 = 134^2 + 907^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 840605 - 2² = 840601 is a prime.

It is a super-3 number, since 3×840605³ = 1781956759813335375, which contains 333 as substring.

It is a plaindrome in base 13.

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 840605.

It is not an unprimeable number, because it can be changed into a prime (840601) 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, 500 + ... + 1389.

It is an arithmetic number, because the mean of its divisors is an integer number (127575).

2⁸⁴⁰⁶⁰⁵ is an apocalyptic number.

It is an amenable number.

840605 is a deficient number, since it is larger than the sum of its proper divisors (179995).

840605 is a wasteful number, since it uses less digits than its factorization.

840605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1983.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 840605 is about 916.8451341421. The cubic root of 840605 is about 94.3765265896.

The spelling of 840605 in words is "eight hundred forty thousand, six hundred five".