55831561 has 2 divisors, whose sum is σ = 55831562. Its totient is φ = 55831560.

The previous prime is 55831547. The next prime is 55831663. The reversal of 55831561 is 16513855.

55831561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 37896336 + 17935225 = 6156^2 + 4235^2 .

It is a cyclic number.

It is not a de Polignac number, because 55831561 - 2⁹ = 55831049 is a prime.

It is not a weakly prime, because it can be changed into another prime (55832561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27915780 + 27915781.

It is an arithmetic number, because the mean of its divisors is an integer number (27915781).

Almost surely, 2^55831561 is an apocalyptic number.

It is an amenable number.

55831561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55831561 is an equidigital number, since it uses as much as digits as its factorization.

55831561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18000, while the sum is 34.

The square root of 55831561 is about 7472.0519939304. The cubic root of 55831561 is about 382.2022653514.

The spelling of 55831561 in words is "fifty-five million, eight hundred thirty-one thousand, five hundred sixty-one".