664626641 has 16 divisors (see below), whose sum is σ = 776630400. Its totient is φ = 568537200.

The previous prime is 664626629. The next prime is 664626643. The reversal of 664626641 is 146626466.

It is a de Polignac number, because none of the positive numbers 2^k-664626641 is a prime.

It is not an unprimeable number, because it can be changed into a prime (664626643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 199691 + ... + 202991.

It is an arithmetic number, because the mean of its divisors is an integer number (48539400).

Almost surely, 2^664626641 is an apocalyptic number.

It is an amenable number.

664626641 is a deficient number, since it is larger than the sum of its proper divisors (112003759).

664626641 is an equidigital number, since it uses as much as digits as its factorization.

664626641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3909 (or 3895 counting only the distinct ones).

The product of its digits is 248832, while the sum is 41.

The square root of 664626641 is about 25780.3537795741. The cubic root of 664626641 is about 872.6884910070.

The spelling of 664626641 in words is "six hundred sixty-four million, six hundred twenty-six thousand, six hundred forty-one".