55561001 has 2 divisors, whose sum is σ = 55561002. Its totient is φ = 55561000.

The previous prime is 55560991. The next prime is 55561043. The reversal of 55561001 is 10016555.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 54405376 + 1155625 = 7376^2 + 1075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-55561001 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (55521001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27780500 + 27780501.

It is an arithmetic number, because the mean of its divisors is an integer number (27780501).

Almost surely, 2^55561001 is an apocalyptic number.

It is an amenable number.

55561001 is a deficient number, since it is larger than the sum of its proper divisors (1).

55561001 is an equidigital number, since it uses as much as digits as its factorization.

55561001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 750, while the sum is 23.

The square root of 55561001 is about 7453.9252075668. The cubic root of 55561001 is about 381.5838807328.

Adding to 55561001 its reverse (10016555), we get a palindrome (65577556).

The spelling of 55561001 in words is "fifty-five million, five hundred sixty-one thousand, one".