320661641 has 2 divisors, whose sum is σ = 320661642. Its totient is φ = 320661640.

The previous prime is 320661623. The next prime is 320661643. The reversal of 320661641 is 146166023.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 246615616 + 74046025 = 15704^2 + 8605^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-320661641 is a prime.

Together with 320661643, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (320661643) 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, 160330820 + 160330821.

It is an arithmetic number, because the mean of its divisors is an integer number (160330821).

Almost surely, 2^320661641 is an apocalyptic number.

It is an amenable number.

320661641 is a deficient number, since it is larger than the sum of its proper divisors (1).

320661641 is an equidigital number, since it uses as much as digits as its factorization.

320661641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 320661641 is about 17907.0276986439. The cubic root of 320661641 is about 684.4614667228.

The spelling of 320661641 in words is "three hundred twenty million, six hundred sixty-one thousand, six hundred forty-one".