7842 has 8 divisors (see below), whose sum is σ = 15696. Its totient is φ = 2612.

The previous prime is 7841. The next prime is 7853. The reversal of 7842 is 2487.

It is a happy number.

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

7842 is an admirable number.

It is a super-2 number, since 2×7842² = 122993928, which contains 22 as substring.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (7841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 648 + ... + 659.

It is an arithmetic number, because the mean of its divisors is an integer number (1962).

7842 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (7848).

7842 is a wasteful number, since it uses less digits than its factorization.

7842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1312.

The product of its digits is 448, while the sum is 21.

The square root of 7842 is about 88.5550676133. Note that the first 3 decimals coincide. The cubic root of 7842 is about 19.8674568899.

It can be divided in two parts, 78 and 42, that added together give a triangular number (120 = T₁₅).

The spelling of 7842 in words is "seven thousand, eight hundred forty-two".