15556100561 has 4 divisors (see below), whose sum is σ = 15887081472. Its totient is φ = 15225119652.

The previous prime is 15556100509. The next prime is 15556100621. The reversal of 15556100561 is 16500165551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16500165551 = 94099 ⋅175349.

It is a de Polignac number, because none of the positive numbers 2^k-15556100561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15556103561) 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 3 ways as a sum of consecutive naturals, for example, 165490385 + ... + 165490478.

It is an arithmetic number, because the mean of its divisors is an integer number (3971770368).

Almost surely, 2^15556100561 is an apocalyptic number.

It is an amenable number.

15556100561 is a deficient number, since it is larger than the sum of its proper divisors (330980911).

15556100561 is an equidigital number, since it uses as much as digits as its factorization.

15556100561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330980910.

The product of its (nonzero) digits is 22500, while the sum is 35.

The spelling of 15556100561 in words is "fifteen billion, five hundred fifty-six million, one hundred thousand, five hundred sixty-one".