920668561 has 2 divisors, whose sum is σ = 920668562. Its totient is φ = 920668560.

The previous prime is 920668543. The next prime is 920668577. The reversal of 920668561 is 165866029.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 623450961 + 297217600 = 24969^2 + 17240^2 .

It is a cyclic number.

It is not a de Polignac number, because 920668561 - 2⁷ = 920668433 is a prime.

It is not a weakly prime, because it can be changed into another prime (920668061) 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, 460334280 + 460334281.

It is an arithmetic number, because the mean of its divisors is an integer number (460334281).

Almost surely, 2^920668561 is an apocalyptic number.

It is an amenable number.

920668561 is a deficient number, since it is larger than the sum of its proper divisors (1).

920668561 is an equidigital number, since it uses as much as digits as its factorization.

920668561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 155520, while the sum is 43.

The square root of 920668561 is about 30342.5206764369. The cubic root of 920668561 is about 972.8243615500.

The spelling of 920668561 in words is "nine hundred twenty million, six hundred sixty-eight thousand, five hundred sixty-one".