840542 has 4 divisors (see below), whose sum is σ = 1260816. Its totient is φ = 420270.

The previous prime is 840523. The next prime is 840547. The reversal of 840542 is 245048.

It is a semiprime because it is the product of two primes.

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 840542.

It is not an unprimeable number, because it can be changed into a prime (840547) by changing a digit.

840542 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210134 + ... + 210137.

It is an arithmetic number, because the mean of its divisors is an integer number (315204).

2⁸⁴⁰⁵⁴² is an apocalyptic number.

840542 is a deficient number, since it is larger than the sum of its proper divisors (420274).

840542 is a wasteful number, since it uses less digits than its factorization.

840542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420273.

The product of its (nonzero) digits is 1280, while the sum is 23.

The square root of 840542 is about 916.8107765510. The cubic root of 840542 is about 94.3741688157.

The spelling of 840542 in words is "eight hundred forty thousand, five hundred forty-two".