55783561 has 2 divisors, whose sum is σ = 55783562. Its totient is φ = 55783560.

The previous prime is 55783549. The next prime is 55783571. The reversal of 55783561 is 16538755.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32319225 + 23464336 = 5685^2 + 4844^2 .

It is a cyclic number.

It is not a de Polignac number, because 55783561 - 2⁷ = 55783433 is a prime.

It is a super-2 number, since 2×55783561² = 6223611355681442, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (55783571) 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, 27891780 + 27891781.

It is an arithmetic number, because the mean of its divisors is an integer number (27891781).

Almost surely, 2^55783561 is an apocalyptic number.

It is an amenable number.

55783561 is a deficient number, since it is larger than the sum of its proper divisors (1).

55783561 is an equidigital number, since it uses as much as digits as its factorization.

55783561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 126000, while the sum is 40.

The square root of 55783561 is about 7468.8393341938. The cubic root of 55783561 is about 382.0927038515.

The spelling of 55783561 in words is "fifty-five million, seven hundred eighty-three thousand, five hundred sixty-one".