556815221 has 2 divisors, whose sum is σ = 556815222. Its totient is φ = 556815220.

The previous prime is 556815209. The next prime is 556815253. The reversal of 556815221 is 122518655.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 338928100 + 217887121 = 18410^2 + 14761^2 .

It is a cyclic number.

It is not a de Polignac number, because 556815221 - 2²² = 552620917 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (556815271) 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, 278407610 + 278407611.

It is an arithmetic number, because the mean of its divisors is an integer number (278407611).

Almost surely, 2^556815221 is an apocalyptic number.

It is an amenable number.

556815221 is a deficient number, since it is larger than the sum of its proper divisors (1).

556815221 is an equidigital number, since it uses as much as digits as its factorization.

556815221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24000, while the sum is 35.

The square root of 556815221 is about 23596.9324489434. The cubic root of 556815221 is about 822.6915428663.

The spelling of 556815221 in words is "five hundred fifty-six million, eight hundred fifteen thousand, two hundred twenty-one".