1561565111556 has 96 divisors (see below), whose sum is σ = 3876406934400. Its totient is φ = 487568277504.

The previous prime is 1561565111549. The next prime is 1561565111567. The reversal of 1561565111556 is 6551115651651.

It is a super-2 number, since 2×1561565111556² (a number of 25 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42130120 + ... + 42167168.

It is an arithmetic number, because the mean of its divisors is an integer number (40379238900).

Almost surely, 2^{1561565111556} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1561565111556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1938203467200).

1561565111556 is an abundant number, since it is smaller than the sum of its proper divisors (2314841822844).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1561565111556 is a wasteful number, since it uses less digits than its factorization.

1561565111556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 38053 (or 38051 counting only the distinct ones).

The product of its digits is 675000, while the sum is 48.

The spelling of 1561565111556 in words is "one trillion, five hundred sixty-one billion, five hundred sixty-five million, one hundred eleven thousand, five hundred fifty-six".