1561105155 has 32 divisors (see below), whose sum is σ = 2648165184. Its totient is φ = 782585856.

The previous prime is 1561105109. The next prime is 1561105157. The reversal of 1561105155 is 5515011651.

It is not a de Polignac number, because 1561105155 - 2¹¹ = 1561103107 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1561105157) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 213927 + ... + 221103.

It is an arithmetic number, because the mean of its divisors is an integer number (82755162).

Almost surely, 2^1561105155 is an apocalyptic number.

1561105155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1561105155 is a deficient number, since it is larger than the sum of its proper divisors (1087060029).

1561105155 is a wasteful number, since it uses less digits than its factorization.

1561105155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8055.

The product of its (nonzero) digits is 3750, while the sum is 30.

The square root of 1561105155 is about 39510.8232640121. The cubic root of 1561105155 is about 1160.0518097648.

The spelling of 1561105155 in words is "one billion, five hundred sixty-one million, one hundred five thousand, one hundred fifty-five".