551555561 has 8 divisors (see below), whose sum is σ = 557305824. Its totient is φ = 545830560.

The previous prime is 551555549. The next prime is 551555573. The reversal of 551555561 is 165555155.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (551555549) and next prime (551555573).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-551555561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (551555581) 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 in 7 ways as a sum of consecutive naturals, for example, 39266 + ... + 51428.

It is an arithmetic number, because the mean of its divisors is an integer number (69663228).

Almost surely, 2^551555561 is an apocalyptic number.

It is an amenable number.

551555561 is a deficient number, since it is larger than the sum of its proper divisors (5750263).

551555561 is a wasteful number, since it uses less digits than its factorization.

551555561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12631.

The product of its digits is 93750, while the sum is 38.

The square root of 551555561 is about 23485.2200543235. The cubic root of 551555561 is about 820.0929703233.

The spelling of 551555561 in words is "five hundred fifty-one million, five hundred fifty-five thousand, five hundred sixty-one".