320407561 has 2 divisors, whose sum is σ = 320407562. Its totient is φ = 320407560.

The previous prime is 320407547. The next prime is 320407597. The reversal of 320407561 is 165704023.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 316163961 + 4243600 = 17781^2 + 2060^2 .

It is a cyclic number.

It is not a de Polignac number, because 320407561 - 2⁹ = 320407049 is a prime.

It is a super-2 number, since 2×320407561² = 205322010291937442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (320407501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160203780 + 160203781.

It is an arithmetic number, because the mean of its divisors is an integer number (160203781).

Almost surely, 2^320407561 is an apocalyptic number.

It is an amenable number.

320407561 is a deficient number, since it is larger than the sum of its proper divisors (1).

320407561 is an equidigital number, since it uses as much as digits as its factorization.

320407561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 320407561 is about 17899.9318713787. The cubic root of 320407561 is about 684.2806386056.

It can be divided in two parts, 32040 and 7561, that added together give a square (39601 = 199²).

The spelling of 320407561 in words is "three hundred twenty million, four hundred seven thousand, five hundred sixty-one".