320645657 has 2 divisors, whose sum is σ = 320645658. Its totient is φ = 320645656.

The previous prime is 320645641. The next prime is 320645669. The reversal of 320645657 is 756546023.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 319837456 + 808201 = 17884^2 + 899^2 .

It is an emirp because it is prime and its reverse (756546023) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 320645657 - 2⁴ = 320645641 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 320645657.

It is not a weakly prime, because it can be changed into another prime (320644657) 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, 160322828 + 160322829.

It is an arithmetic number, because the mean of its divisors is an integer number (160322829).

Almost surely, 2^320645657 is an apocalyptic number.

It is an amenable number.

320645657 is a deficient number, since it is larger than the sum of its proper divisors (1).

320645657 is an equidigital number, since it uses as much as digits as its factorization.

320645657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151200, while the sum is 38.

The square root of 320645657 is about 17906.5813878585. The cubic root of 320645657 is about 684.4500937651.

The spelling of 320645657 in words is "three hundred twenty million, six hundred forty-five thousand, six hundred fifty-seven".