556688921 has 2 divisors, whose sum is σ = 556688922. Its totient is φ = 556688920.

The previous prime is 556688903. The next prime is 556688947. The reversal of 556688921 is 129886655.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 465696400 + 90992521 = 21580^2 + 9539^2 .

It is a cyclic number.

It is not a de Polignac number, because 556688921 - 2¹⁸ = 556426777 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 556688921.

It is not a weakly prime, because it can be changed into another prime (556688981) 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, 278344460 + 278344461.

It is an arithmetic number, because the mean of its divisors is an integer number (278344461).

Almost surely, 2^556688921 is an apocalyptic number.

It is an amenable number.

556688921 is a deficient number, since it is larger than the sum of its proper divisors (1).

556688921 is an equidigital number, since it uses as much as digits as its factorization.

556688921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1036800, while the sum is 50.

The square root of 556688921 is about 23594.2561018567. The cubic root of 556688921 is about 822.6293356355.

The spelling of 556688921 in words is "five hundred fifty-six million, six hundred eighty-eight thousand, nine hundred twenty-one".