55555555561 has 8 divisors (see below), whose sum is σ = 60729500448. Its totient is φ = 50402184000.

The previous prime is 55555555543. The next prime is 55555555619. The reversal of 55555555561 is 16555555555.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 55555555561 - 2¹¹ = 55555553513 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 55555555499 and 55555555508.

It is not an unprimeable number, because it can be changed into a prime (55555555061) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5137680 + ... + 5148481.

It is an arithmetic number, because the mean of its divisors is an integer number (7591187556).

Almost surely, 2^55555555561 is an apocalyptic number.

It is an amenable number.

55555555561 is a deficient number, since it is larger than the sum of its proper divisors (5173944887).

55555555561 is a wasteful number, since it uses less digits than its factorization.

55555555561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10286663.

The product of its digits is 11718750, while the sum is 52.

It can be divided in two parts, 555555 and 55561, that added together give a palindrome (611116).

The spelling of 55555555561 in words is "fifty-five billion, five hundred fifty-five million, five hundred fifty-five thousand, five hundred sixty-one".