555331561 has 2 divisors, whose sum is σ = 555331562. Its totient is φ = 555331560.

The previous prime is 555331559. The next prime is 555331681. The reversal of 555331561 is 165133555.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 444155625 + 111175936 = 21075^2 + 10544^2 .

It is a cyclic number.

It is not a de Polignac number, because 555331561 - 2¹ = 555331559 is a prime.

Together with 555331559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (555331531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 277665780 + 277665781.

It is an arithmetic number, because the mean of its divisors is an integer number (277665781).

Almost surely, 2^555331561 is an apocalyptic number.

It is an amenable number.

555331561 is a deficient number, since it is larger than the sum of its proper divisors (1).

555331561 is an equidigital number, since it uses as much as digits as its factorization.

555331561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 33750, while the sum is 34.

The square root of 555331561 is about 23565.4739184257. The cubic root of 555331561 is about 821.9601929760.

The spelling of 555331561 in words is "five hundred fifty-five million, three hundred thirty-one thousand, five hundred sixty-one".