56728121 has 2 divisors, whose sum is σ = 56728122. Its totient is φ = 56728120.

The previous prime is 56728079. The next prime is 56728127. The reversal of 56728121 is 12182765.

56728121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 46717225 + 10010896 = 6835^2 + 3164^2 .

It is a cyclic number.

It is not a de Polignac number, because 56728121 - 2⁶ = 56728057 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is equal to p_3379217 and since 56728121 and 3379217 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (56728127) 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, 28364060 + 28364061.

It is an arithmetic number, because the mean of its divisors is an integer number (28364061).

Almost surely, 2^56728121 is an apocalyptic number.

It is an amenable number.

56728121 is a deficient number, since it is larger than the sum of its proper divisors (1).

56728121 is an equidigital number, since it uses as much as digits as its factorization.

56728121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6720, while the sum is 32.

The square root of 56728121 is about 7531.8072864353. The cubic root of 56728121 is about 384.2372507572.

The spelling of 56728121 in words is "fifty-six million, seven hundred twenty-eight thousand, one hundred twenty-one".