18561001 has 2 divisors, whose sum is σ = 18561002. Its totient is φ = 18561000.

The previous prime is 18560981. The next prime is 18561029. The reversal of 18561001 is 10016581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18071001 + 490000 = 4251^2 + 700^2 .

It is a cyclic number.

It is not a de Polignac number, because 18561001 - 2⁷ = 18560873 is a prime.

It is not a weakly prime, because it can be changed into another prime (18561091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9280500 + 9280501.

It is an arithmetic number, because the mean of its divisors is an integer number (9280501).

Almost surely, 2^18561001 is an apocalyptic number.

It is an amenable number.

18561001 is a deficient number, since it is larger than the sum of its proper divisors (1).

18561001 is an equidigital number, since it uses as much as digits as its factorization.

18561001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 22.

The square root of 18561001 is about 4308.2480197872. The cubic root of 18561001 is about 264.7689976954.

Adding to 18561001 its reverse (10016581), we get a palindrome (28577582).

The spelling of 18561001 in words is "eighteen million, five hundred sixty-one thousand, one".