320356661 has 2 divisors, whose sum is σ = 320356662. Its totient is φ = 320356660.

The previous prime is 320356643. The next prime is 320356667. The reversal of 320356661 is 166653023.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 278689636 + 41667025 = 16694^2 + 6455^2 .

It is a cyclic number.

It is not a de Polignac number, because 320356661 - 2¹⁴ = 320340277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (320356667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160178330 + 160178331.

It is an arithmetic number, because the mean of its divisors is an integer number (160178331).

Almost surely, 2^320356661 is an apocalyptic number.

It is an amenable number.

320356661 is a deficient number, since it is larger than the sum of its proper divisors (1).

320356661 is an equidigital number, since it uses as much as digits as its factorization.

320356661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 19440, while the sum is 32.

The square root of 320356661 is about 17898.5100217867. The cubic root of 320356661 is about 684.2444017069.

The spelling of 320356661 in words is "three hundred twenty million, three hundred fifty-six thousand, six hundred sixty-one".