55820561 has 2 divisors, whose sum is σ = 55820562. Its totient is φ = 55820560.

The previous prime is 55820539. The next prime is 55820573. The reversal of 55820561 is 16502855.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 38440000 + 17380561 = 6200^2 + 4169^2 .

It is a cyclic number.

It is not a de Polignac number, because 55820561 - 2⁶ = 55820497 is a prime.

It is not a weakly prime, because it can be changed into another prime (55820521) 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, 27910280 + 27910281.

It is an arithmetic number, because the mean of its divisors is an integer number (27910281).

Almost surely, 2^55820561 is an apocalyptic number.

It is an amenable number.

55820561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55820561 is an equidigital number, since it uses as much as digits as its factorization.

55820561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12000, while the sum is 32.

The square root of 55820561 is about 7471.3158814228. The cubic root of 55820561 is about 382.1771630557.

The spelling of 55820561 in words is "fifty-five million, eight hundred twenty thousand, five hundred sixty-one".