6445550581 has 2 divisors, whose sum is σ = 6445550582. Its totient is φ = 6445550580.

The previous prime is 6445550497. The next prime is 6445550593. The reversal of 6445550581 is 1850555446.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5247698481 + 1197852100 = 72441^2 + 34610^2 .

It is a cyclic number.

It is not a de Polignac number, because 6445550581 - 2⁷ = 6445550453 is a prime.

It is a super-2 number, since 2×6445550581² = 83090244584458875122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6445553581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3222775290 + 3222775291.

It is an arithmetic number, because the mean of its divisors is an integer number (3222775291).

Almost surely, 2^6445550581 is an apocalyptic number.

It is an amenable number.

6445550581 is a deficient number, since it is larger than the sum of its proper divisors (1).

6445550581 is an equidigital number, since it uses as much as digits as its factorization.

6445550581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 480000, while the sum is 43.

The square root of 6445550581 is about 80284.1863694215. The cubic root of 6445550581 is about 1861.0298552578.

The spelling of 6445550581 in words is "six billion, four hundred forty-five million, five hundred fifty thousand, five hundred eighty-one".