556016821 has 2 divisors, whose sum is σ = 556016822. Its totient is φ = 556016820.

The previous prime is 556016777. The next prime is 556016843. The reversal of 556016821 is 128610655.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 555780625 + 236196 = 23575^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 556016821 - 2²⁵ = 522462389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (556016221) 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, 278008410 + 278008411.

It is an arithmetic number, because the mean of its divisors is an integer number (278008411).

Almost surely, 2^556016821 is an apocalyptic number.

It is an amenable number.

556016821 is a deficient number, since it is larger than the sum of its proper divisors (1).

556016821 is an equidigital number, since it uses as much as digits as its factorization.

556016821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 14400, while the sum is 34.

The square root of 556016821 is about 23580.0089270551. The cubic root of 556016821 is about 822.2981441872.

The spelling of 556016821 in words is "five hundred fifty-six million, sixteen thousand, eight hundred twenty-one".