55116781 has 2 divisors, whose sum is σ = 55116782. Its totient is φ = 55116780.

The previous prime is 55116779. The next prime is 55116827. The reversal of 55116781 is 18761155.

55116781 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., 45562500 + 9554281 = 6750^2 + 3091^2 .

It is a cyclic number.

It is not a de Polignac number, because 55116781 - 2¹ = 55116779 is a prime.

It is a super-2 number, since 2×55116781² = 6075719095603922, which contains 22 as substring.

Together with 55116779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55116181) 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, 27558390 + 27558391.

It is an arithmetic number, because the mean of its divisors is an integer number (27558391).

Almost surely, 2^55116781 is an apocalyptic number.

It is an amenable number.

55116781 is a deficient number, since it is larger than the sum of its proper divisors (1).

55116781 is an equidigital number, since it uses as much as digits as its factorization.

55116781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8400, while the sum is 34.

The square root of 55116781 is about 7424.0676855751. The cubic root of 55116781 is about 380.5642149457.

The spelling of 55116781 in words is "fifty-five million, one hundred sixteen thousand, seven hundred eighty-one".