15561600561 has 24 divisors (see below), whose sum is σ = 24225777576. Its totient is φ = 9568915200.

The previous prime is 15561600559. The next prime is 15561600577. The reversal of 15561600561 is 16500616551.

It can be written as a sum of positive squares in 4 ways, for example, as 583512336 + 14978088225 = 24156^2 + 122385^2 .

It is not a de Polignac number, because 15561600561 - 2¹ = 15561600559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15561200561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 101101 + ... + 203333.

It is an arithmetic number, because the mean of its divisors is an integer number (1009407399).

Almost surely, 2^15561600561 is an apocalyptic number.

It is an amenable number.

15561600561 is a deficient number, since it is larger than the sum of its proper divisors (8664177015).

15561600561 is a wasteful number, since it uses less digits than its factorization.

15561600561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103553 (or 103550 counting only the distinct ones).

The product of its (nonzero) digits is 27000, while the sum is 36.

The spelling of 15561600561 in words is "fifteen billion, five hundred sixty-one million, six hundred thousand, five hundred sixty-one".