646768016 has 10 divisors (see below), whose sum is σ = 1253113062. Its totient is φ = 323384000.

The previous prime is 646767983. The next prime is 646768019. The reversal of 646768016 is 610867646.

It can be written as a sum of positive squares in only one way, i.e., 329785600 + 316982416 = 18160^2 + 17804^2 .

It is not an unprimeable number, because it can be changed into a prime (646768019) 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, 20211485 + ... + 20211516.

Almost surely, 2^646768016 is an apocalyptic number.

It is an amenable number.

646768016 is a deficient number, since it is larger than the sum of its proper divisors (606345046).

646768016 is a wasteful number, since it uses less digits than its factorization.

646768016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40423009 (or 40423003 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 44.

The square root of 646768016 is about 25431.6341590547. The cubic root of 646768016 is about 864.8009904478.

The spelling of 646768016 in words is "six hundred forty-six million, seven hundred sixty-eight thousand, sixteen".