15550566561 has 6 divisors (see below), whose sum is σ = 22461929490. Its totient is φ = 10367044368.

The previous prime is 15550566533. The next prime is 15550566583. The reversal of 15550566561 is 16566505551.

15550566561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 14873265936 + 677300625 = 121956^2 + 26025^2 .

It is not a de Polignac number, because 15550566561 - 2¹⁷ = 15550435489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15550566461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 863920356 + ... + 863920373.

It is an arithmetic number, because the mean of its divisors is an integer number (3743654915).

Almost surely, 2^15550566561 is an apocalyptic number.

It is an amenable number.

15550566561 is a deficient number, since it is larger than the sum of its proper divisors (6911362929).

15550566561 is a wasteful number, since it uses less digits than its factorization.

15550566561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1727840735 (or 1727840732 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 45.

The spelling of 15550566561 in words is "fifteen billion, five hundred fifty million, five hundred sixty-six thousand, five hundred sixty-one".