840645 has 32 divisors (see below), whose sum is σ = 1612800. Its totient is φ = 412992.

The previous prime is 840643. The next prime is 840661. The reversal of 840645 is 546048.

It is not a de Polignac number, because 840645 - 2¹ = 840643 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840643) 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 31 ways as a sum of consecutive naturals, for example, 1516 + ... + 1994.

It is an arithmetic number, because the mean of its divisors is an integer number (50400).

2⁸⁴⁰⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

840645 is a deficient number, since it is larger than the sum of its proper divisors (772155).

840645 is a wasteful number, since it uses less digits than its factorization.

840645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 840645 is about 916.8669478174. The cubic root of 840645 is about 94.3780235278.

It can be divided in two parts, 840 and 645, that added together give a triangular number (1485 = T₅₄).

The spelling of 840645 in words is "eight hundred forty thousand, six hundred forty-five".