678131842 has 4 divisors (see below), whose sum is σ = 1017197766. Its totient is φ = 339065920.

The previous prime is 678131771. The next prime is 678131843. The reversal of 678131842 is 248131876.

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

It can be written as a sum of positive squares in only one way, i.e., 608559561 + 69572281 = 24669^2 + 8341^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 678131795 and 678131804.

It is not an unprimeable number, because it can be changed into a prime (678131843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 169532959 + ... + 169532962.

Almost surely, 2^678131842 is an apocalyptic number.

678131842 is a deficient number, since it is larger than the sum of its proper divisors (339065924).

678131842 is a wasteful number, since it uses less digits than its factorization.

678131842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 339065923.

The product of its digits is 64512, while the sum is 40.

The square root of 678131842 is about 26040.9646902721. The cubic root of 678131842 is about 878.5599044232.

The spelling of 678131842 in words is "six hundred seventy-eight million, one hundred thirty-one thousand, eight hundred forty-two".