9001561 has 2 divisors, whose sum is σ = 9001562. Its totient is φ = 9001560.

The previous prime is 9001523. The next prime is 9001621. The reversal of 9001561 is 1651009.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5175625 + 3825936 = 2275^2 + 1956^2 .

It is a cyclic number.

It is not a de Polignac number, because 9001561 - 2¹⁵ = 8968793 is a prime.

It is not a weakly prime, because it can be changed into another prime (9001511) 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, 4500780 + 4500781.

It is an arithmetic number, because the mean of its divisors is an integer number (4500781).

Almost surely, 2^9001561 is an apocalyptic number.

It is an amenable number.

9001561 is a deficient number, since it is larger than the sum of its proper divisors (1).

9001561 is an equidigital number, since it uses as much as digits as its factorization.

9001561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 270, while the sum is 22.

The square root of 9001561 is about 3000.2601553865. The cubic root of 9001561 is about 208.0204075761.

The spelling of 9001561 in words is "nine million, one thousand, five hundred sixty-one".