664807751 has 4 divisors (see below), whose sum is σ = 668480904. Its totient is φ = 661134600.

The previous prime is 664807747. The next prime is 664807771. The reversal of 664807751 is 157708466.

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

It is a cyclic number.

It is not a de Polignac number, because 664807751 - 2² = 664807747 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664807711) 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 in 3 ways as a sum of consecutive naturals, for example, 1836305 + ... + 1836666.

It is an arithmetic number, because the mean of its divisors is an integer number (167120226).

Almost surely, 2^664807751 is an apocalyptic number.

664807751 is a deficient number, since it is larger than the sum of its proper divisors (3673153).

664807751 is a wasteful number, since it uses less digits than its factorization.

664807751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3673152.

The product of its (nonzero) digits is 282240, while the sum is 44.

The square root of 664807751 is about 25783.8660987836. The cubic root of 664807751 is about 872.7677526800.

The spelling of 664807751 in words is "six hundred sixty-four million, eight hundred seven thousand, seven hundred fifty-one".