8561801491 has 2 divisors, whose sum is σ = 8561801492. Its totient is φ = 8561801490.

The previous prime is 8561801473. The next prime is 8561801531. The reversal of 8561801491 is 1941081658.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 8561801491 - 2⁷ = 8561801363 is a prime.

It is not a weakly prime, because it can be changed into another prime (8561801401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4280900745 + 4280900746.

It is an arithmetic number, because the mean of its divisors is an integer number (4280900746).

Almost surely, 2^8561801491 is an apocalyptic number.

8561801491 is a deficient number, since it is larger than the sum of its proper divisors (1).

8561801491 is an equidigital number, since it uses as much as digits as its factorization.

8561801491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 69120, while the sum is 43.

The square root of 8561801491 is about 92530.0031935588. The cubic root of 8561801491 is about 2045.7617367000.

The spelling of 8561801491 in words is "eight billion, five hundred sixty-one million, eight hundred one thousand, four hundred ninety-one".