551656561 has 2 divisors, whose sum is σ = 551656562. Its totient is φ = 551656560.

The previous prime is 551656559. The next prime is 551656571. The reversal of 551656561 is 165656155.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 388838961 + 162817600 = 19719^2 + 12760^2 .

It is a cyclic number.

It is not a de Polignac number, because 551656561 - 2¹ = 551656559 is a prime.

It is a super-2 number, since 2×551656561² = 608649922588693442, which contains 22 as substring.

Together with 551656559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (551656571) 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, 275828280 + 275828281.

It is an arithmetic number, because the mean of its divisors is an integer number (275828281).

Almost surely, 2^551656561 is an apocalyptic number.

It is an amenable number.

551656561 is a deficient number, since it is larger than the sum of its proper divisors (1).

551656561 is an equidigital number, since it uses as much as digits as its factorization.

551656561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 135000, while the sum is 40.

The square root of 551656561 is about 23487.3702444527. The cubic root of 551656561 is about 820.1430253196.

The spelling of 551656561 in words is "five hundred fifty-one million, six hundred fifty-six thousand, five hundred sixty-one".