556840981 has 2 divisors, whose sum is σ = 556840982. Its totient is φ = 556840980.

The previous prime is 556840979. The next prime is 556841011. The reversal of 556840981 is 189048655.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 353778481 + 203062500 = 18809^2 + 14250^2 .

It is a cyclic number.

It is not a de Polignac number, because 556840981 - 2¹ = 556840979 is a prime.

It is a super-2 number, since 2×556840981² = 620143756242084722, which contains 22 as substring.

Together with 556840979, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (556840931) 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, 278420490 + 278420491.

It is an arithmetic number, because the mean of its divisors is an integer number (278420491).

Almost surely, 2^556840981 is an apocalyptic number.

It is an amenable number.

556840981 is a deficient number, since it is larger than the sum of its proper divisors (1).

556840981 is an equidigital number, since it uses as much as digits as its factorization.

556840981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 345600, while the sum is 46.

The square root of 556840981 is about 23597.4782762905. The cubic root of 556840981 is about 822.7042294253.

The spelling of 556840981 in words is "five hundred fifty-six million, eight hundred forty thousand, nine hundred eighty-one".