15561554855 has 32 divisors (see below), whose sum is σ = 23318281728. Its totient is φ = 9685468800.

The previous prime is 15561554851. The next prime is 15561554873. The reversal of 15561554855 is 55845516551.

It is not a de Polignac number, because 15561554855 - 2² = 15561554851 is a prime.

It is a Smith number, since the sum of its digits (50) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15561554851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 216125 + ... + 278985.

It is an arithmetic number, because the mean of its divisors is an integer number (728696304).

Almost surely, 2^15561554855 is an apocalyptic number.

15561554855 is a deficient number, since it is larger than the sum of its proper divisors (7756726873).

15561554855 is a wasteful number, since it uses less digits than its factorization.

15561554855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63527.

The product of its digits is 3000000, while the sum is 50.

The spelling of 15561554855 in words is "fifteen billion, five hundred sixty-one million, five hundred fifty-four thousand, eight hundred fifty-five".