668512751 has 4 divisors (see below), whose sum is σ = 672770952. Its totient is φ = 664254552.

The previous prime is 668512729. The next prime is 668512759. The reversal of 668512751 is 157215866.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-668512751 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 668512699 and 668512708.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668512759) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2128865 + ... + 2129178.

It is an arithmetic number, because the mean of its divisors is an integer number (168192738).

Almost surely, 2^668512751 is an apocalyptic number.

668512751 is a deficient number, since it is larger than the sum of its proper divisors (4258201).

668512751 is a wasteful number, since it uses less digits than its factorization.

668512751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4258200.

The product of its digits is 100800, while the sum is 41.

The square root of 668512751 is about 25855.6135297540. The cubic root of 668512751 is about 874.3860731876.

The spelling of 668512751 in words is "six hundred sixty-eight million, five hundred twelve thousand, seven hundred fifty-one".