840861 has 20 divisors (see below), whose sum is σ = 1436512. Its totient is φ = 480168.

The previous prime is 840859. The next prime is 840863. The reversal of 840861 is 168048.

It is an interprime number because it is at equal distance from previous prime (840859) and next prime (840863).

It is not a de Polignac number, because 840861 - 2¹ = 840859 is a prime.

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

It is an Ulam number.

It is a Curzon number.

840861 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840863) 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 19 ways as a sum of consecutive naturals, for example, 175 + ... + 1308.

2⁸⁴⁰⁸⁶¹ is an apocalyptic number.

840861 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

840861 is a deficient number, since it is larger than the sum of its proper divisors (595651).

840861 is a wasteful number, since it uses less digits than its factorization.

840861 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1502 (or 1493 counting only the distinct ones).

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

The square root of 840861 is about 916.9847326973. The cubic root of 840861 is about 94.3861061736.

The spelling of 840861 in words is "eight hundred forty thousand, eight hundred sixty-one".