15155566561 has 4 divisors (see below), whose sum is σ = 15478025472. Its totient is φ = 14833107652.

The previous prime is 15155566549. The next prime is 15155566577. The reversal of 15155566561 is 16566555151.

It is a happy number.

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: 16566555151 = 39733 ⋅416947.

It is a cyclic number.

It is not a de Polignac number, because 15155566561 - 2⁵ = 15155566529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15155566061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 161229385 + ... + 161229478.

It is an arithmetic number, because the mean of its divisors is an integer number (3869506368).

Almost surely, 2^15155566561 is an apocalyptic number.

It is an amenable number.

15155566561 is a deficient number, since it is larger than the sum of its proper divisors (322458911).

15155566561 is an equidigital number, since it uses as much as digits as its factorization.

15155566561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322458910.

The product of its digits is 675000, while the sum is 46.

The spelling of 15155566561 in words is "fifteen billion, one hundred fifty-five million, five hundred sixty-six thousand, five hundred sixty-one".