668680042 has 8 divisors (see below), whose sum is σ = 1003135716. Its totient is φ = 334301472.

The previous prime is 668680037. The next prime is 668680049. The reversal of 668680042 is 240086866.

It can be written as a sum of positive squares in 2 ways, for example, as 621056241 + 47623801 = 24921^2 + 6901^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 668679977 and 668680004.

It is not an unprimeable number, because it can be changed into a prime (668680049) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13668 + ... + 39040.

Almost surely, 2^668680042 is an apocalyptic number.

668680042 is a deficient number, since it is larger than the sum of its proper divisors (334455674).

668680042 is a wasteful number, since it uses less digits than its factorization.

668680042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38552.

The product of its (nonzero) digits is 110592, while the sum is 40.

The square root of 668680042 is about 25858.8484275692. The cubic root of 668680042 is about 874.4590035944.

The spelling of 668680042 in words is "six hundred sixty-eight million, six hundred eighty thousand, forty-two".