55728181 has 2 divisors, whose sum is σ = 55728182. Its totient is φ = 55728180.

The previous prime is 55728163. The next prime is 55728187. The reversal of 55728181 is 18182755.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 48790225 + 6937956 = 6985^2 + 2634^2 .

It is a cyclic number.

It is not a de Polignac number, because 55728181 - 2¹¹ = 55726133 is a prime.

It is a super-2 number, since 2×55728181² = 6211260315137522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 55728181.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55728187) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27864090 + 27864091.

It is an arithmetic number, because the mean of its divisors is an integer number (27864091).

Almost surely, 2^55728181 is an apocalyptic number.

It is an amenable number.

55728181 is a deficient number, since it is larger than the sum of its proper divisors (1).

55728181 is an equidigital number, since it uses as much as digits as its factorization.

55728181 is an evil number, because the sum of its binary digits is even.

The product of its digits is 22400, while the sum is 37.

The square root of 55728181 is about 7465.1310102369. The cubic root of 55728181 is about 381.9662191558.

The spelling of 55728181 in words is "fifty-five million, seven hundred twenty-eight thousand, one hundred eighty-one".