405555550555561 has 6 divisors (see below), whose sum is σ = 471768701666730. Its totient is φ = 347619043333296.

The previous prime is 405555550555559. The next prime is 405555550555583. The reversal of 405555550555561 is 165555055555504.

It can be written as a sum of positive squares in only one way, i.e., 206487013558336 + 199068536997225 = 14369656^2 + 14109165^2 .

It is not a de Polignac number, because 405555550555561 - 2¹ = 405555550555559 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 405555550555561.

It is not an unprimeable number, because it can be changed into a prime (405555550555541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4138321944396 + ... + 4138321944493.

It is an arithmetic number, because the mean of its divisors is an integer number (78628116944455).

Almost surely, 2^{405555550555561} is an apocalyptic number.

It is an amenable number.

405555550555561 is a deficient number, since it is larger than the sum of its proper divisors (66213151111169).

405555550555561 is an equidigital number, since it uses as much as digits as its factorization.

405555550555561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8276643888903 (or 8276643888896 counting only the distinct ones).

The product of its (nonzero) digits is 234375000, while the sum is 61.

The spelling of 405555550555561 in words is "four hundred five trillion, five hundred fifty-five billion, five hundred fifty million, five hundred fifty-five thousand, five hundred sixty-one".