551567981 has 2 divisors, whose sum is σ = 551567982. Its totient is φ = 551567980.

The previous prime is 551567971. The next prime is 551567999. The reversal of 551567981 is 189765155.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 292068100 + 259499881 = 17090^2 + 16109^2 .

It is a cyclic number.

It is not a de Polignac number, because 551567981 - 2²⁶ = 484459117 is a prime.

It is a super-2 number, since 2×551567981² = 608454475328832722, which contains 22 as substring.

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 (551567971) 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, 275783990 + 275783991.

It is an arithmetic number, because the mean of its divisors is an integer number (275783991).

Almost surely, 2^551567981 is an apocalyptic number.

It is an amenable number.

551567981 is a deficient number, since it is larger than the sum of its proper divisors (1).

551567981 is an equidigital number, since it uses as much as digits as its factorization.

551567981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 378000, while the sum is 47.

The square root of 551567981 is about 23485.4844744578. The cubic root of 551567981 is about 820.0991259306.

The spelling of 551567981 in words is "five hundred fifty-one million, five hundred sixty-seven thousand, nine hundred eighty-one".