666648842 has 4 divisors (see below), whose sum is σ = 999973266. Its totient is φ = 333324420.

The previous prime is 666648793. The next prime is 666648881. The reversal of 666648842 is 248846666.

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., 446096641 + 220552201 = 21121^2 + 14851^2 .

It is an unprimeable number.

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, 166662209 + ... + 166662212.

Almost surely, 2^666648842 is an apocalyptic number.

666648842 is a deficient number, since it is larger than the sum of its proper divisors (333324424).

666648842 is a wasteful number, since it uses less digits than its factorization.

666648842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333324423.

The product of its digits is 2654208, while the sum is 50.

The square root of 666648842 is about 25819.5437992231. The cubic root of 666648842 is about 873.5726790266.

The spelling of 666648842 in words is "six hundred sixty-six million, six hundred forty-eight thousand, eight hundred forty-two".