668481766 has 4 divisors (see below), whose sum is σ = 1002722652. Its totient is φ = 334240882.

The previous prime is 668481763. The next prime is 668481787. The reversal of 668481766 is 667184866.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 667184866 = 2 ⋅333592433.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668481761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 167120440 + ... + 167120443.

It is an arithmetic number, because the mean of its divisors is an integer number (250680663).

Almost surely, 2^668481766 is an apocalyptic number.

668481766 is a deficient number, since it is larger than the sum of its proper divisors (334240886).

668481766 is a wasteful number, since it uses less digits than its factorization.

668481766 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334240885.

The product of its digits is 2322432, while the sum is 52.

The square root of 668481766 is about 25855.0143299129. The cubic root of 668481766 is about 874.3725639608.

The spelling of 668481766 in words is "six hundred sixty-eight million, four hundred eighty-one thousand, seven hundred sixty-six".