55555561 has 8 divisors (see below), whose sum is σ = 57717000. Its totient is φ = 53410560.

The previous prime is 55555559. The next prime is 55555573. The reversal of 55555561 is 16555555.

It can be written as a sum of positive squares in 4 ways, for example, as 14017536 + 41538025 = 3744^2 + 6445^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 55555561 - 2¹ = 55555559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 55555561.

It is not an unprimeable number, because it can be changed into a prime (55555531) 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 in 7 ways as a sum of consecutive naturals, for example, 3015 + ... + 10963.

It is an arithmetic number, because the mean of its divisors is an integer number (7214625).

Almost surely, 2^55555561 is an apocalyptic number.

It is an amenable number.

55555561 is a deficient number, since it is larger than the sum of its proper divisors (2161439).

55555561 is a wasteful number, since it uses less digits than its factorization.

55555561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8219.

The product of its digits is 93750, while the sum is 37.

The square root of 55555561 is about 7453.5602902237. The cubic root of 55555561 is about 381.5714266491.

The spelling of 55555561 in words is "fifty-five million, five hundred fifty-five thousand, five hundred sixty-one".