840042 has 48 divisors (see below), whose sum is σ = 2134080. Its totient is φ = 233856.

The previous prime is 840023. The next prime is 840053. The reversal of 840042 is 240048.

840042 = 29² + 30² + ... + 136².

It is a happy number.

840042 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 839997 and 840024.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7378 + ... + 7490.

It is an arithmetic number, because the mean of its divisors is an integer number (44460).

2⁸⁴⁰⁰⁴² is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 840042, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1067040).

840042 is an abundant number, since it is smaller than the sum of its proper divisors (1294038).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

840042 is a wasteful number, since it uses less digits than its factorization.

840042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 840042 is about 916.5380515832. The cubic root of 840042 is about 94.3554521448.

The spelling of 840042 in words is "eight hundred forty thousand, forty-two".